TMC2005-JT ARCNET 5 Port HUB Controller Data Sheet - SMSC

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SMSC TMC2005-JT 

 

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TMC2005-JT 

 

 

 
 
 
 
 

ARCNET 5 Port HUB Controller  

 

FEATURES 

 

ƒ

 

ARCNET HUB Circuit for ARCNET Protocol 
(Data Rate From 156.25Kbps to 10Mbps) 

ƒ

 

Able to Connect Various Transceivers Directly 

ƒ

 

Device Includes TX/RX Timing Circuit for 5 Port 
Hub and Direction Control Circuit, Jitter Correct 
Circuit and Noise Cancel Circuit 

ƒ

 

Easy to Design 8 or 12 Port Hub 

 

ƒ

 

Can Connect with HYC9088 in Normal Mode 

ƒ

 

Can Connect with RS485 Transceiver, 
HYC5000/4000/2000, Opt Module and TTL 
Interface in Backplane Mode 

ƒ

 

Supports both Normal and Backplane Mode at 
the Same Time for Media Conversion 

ƒ

 

+ 5V Single Power

 

 

GENERAL DESCRIPTION

 

 
When configuring a network, the maximum number of nodes and the maximum cable length are limited by the electric 
capacity of the transceiver. In this case, the network is expanded by an equipment called a “HUB” or “repeater”.  It 
maybe necessary to have a converter between coax, T/P and the fiber cable. It is easy to design a HUB or a repeater 
because the TMC2005 has various features for expanding such network. 
 
It can connect with HYC9088, RS485 transceiver, HYC5000/4000/2000 and TTL interface for optical module. It can 
connect with three different transceivers at the same time and convert the media of each. (The data rate cannot be 
converted. It is necessary to operate all nodes in the same network at the same data rate). The Hubs can be 
expanded by connecting two or more TMC2005 chips. By setting one of 5 ports to open-drain output, the Hub can be 
expanded to either 12 or 16 ports. 

 
 
 
 
 
 

 

ORDERING INFORMATION 

Order Number(s): 

 

TMC2005-JT for 64 pin, TQFP Lead-Free RoHS Compliant Package 

 

 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 2 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

   

80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123 

 
 

Copyright © 2007 SMSC or its subsidiaries. All rights reserved. 

 
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete 
information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no 
responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without 
notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information 
does not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of 
SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's 
standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or 
errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon 
request. SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure 
could cause or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC 
and further testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms 
of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems 
Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.  
 
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES 
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND 
ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY 
DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR 
REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC 
OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD TO 
HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 
DAMAGES. 
 
 
 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 3  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TABLE OF CONTENTS

 

FEATURES..................................................................................................................................................................1

 

GENERAL DESCRIPTION.......................................................................................................................................1

 

PIN CONFIGURATION ............................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................6

 

TX/RX

 

I

NTERFACE

....................................................................................................................................................7

 

O

PERATING 

M

ODE 

S

ETUP

..........................................................................................................................................8

 

PLL ...........................................................................................................................................................................8

 

O

THER 

S

IGNALS

........................................................................................................................................................9

 

OPERATIONAL DESCRIPTION...........................................................................................................................10

 

D

IRECTION 

D

ETERMINATION

...................................................................................................................................10

 

D

IRECTION 

R

ELEASE

...............................................................................................................................................10

 

J

ITTER 

F

ILTER

..........................................................................................................................................................10

 

O

PTION 

F

EATURE FOR 

J

ITTER 

F

ILTERING

.................................................................................................................11

 

O

PTION 

F

EATURE FOR 

N

OISE 

C

UT MODE

.................................................................................................................11

 

APPLICATION

 

NOTES ........................................................................................................................................12

 

PORT GROUP...........................................................................................................................................................20

 

V

ARIOUS 

S

ETUP

.......................................................................................................................................................20

 

E

XAMPLE 

F

OR 

O

PERATION 

M

ODE 

S

ETUP 

T

E

ACH 

P

ORT

........................................................................................20

 

N

OTE FOR 

U

NUSED PORT

.........................................................................................................................................20

 

E

XAMPLE FOR 

P

OWER

-O

R

ESET 

C

IRCUIT

..............................................................................................................20

 

CONNECTING THE TMC2005 WITH INTERNAL PLL...................................................................................21

 

M

ETHOD 

T

C

ONNECT 

A

 

C

RYSTAL 

C

LOCK

.............................................................................................................22

 

N

PLLTST

 PIN

..........................................................................................................................................................22

 

CASCADING CONNECTION ................................................................................................................................23

 

R

ING 

N

ETWORK 

W

ITH THE 

TMC2005.....................................................................................................................26

 

MAXIMUM

 

GUARANTEED

 

RATINGS*............................................................................................................27

 

STANDARD

 

OPERATING

 

CONDITION ............................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

INPUT

 

PIN ..................................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

OUTPUT

 

PIN ..............................................................................................................28

 

AC

 

CHARACTERISTIC

 

-

 

CLOCK

 AND 

RESET ...................................................................................................28

 

AC

 

CHARACTERISTIC

 

 

R

X WAVEFORMS AND 

T

X WAVEFORMS

........................................................................29

 

TMC2005-JT 64 PIN TQFP PACKAGE OUTLINE .............................................................................................31

 

 
 
 
 
 
 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 4 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 

PIN CONFIGURATION 

 

 
 

RX

IN

A

0

SA

TX

E

N

A

0

LA

MA

RX

IN

A

1

TX

E

N

A

1

VD

D

6

VSS

8

RX

IN

B

0

SB

TX

E

N

B

0

LB

MB

RX

IN

B

1

VS

S5

VS

S3

AV

SS

AGS

LP

AV

D

D

VD

D

3

VD

D

4

VS

S4

XT

LO

XT

L

I

VD

D

2

nPL

L

T

S

T

RX

FL

T

R0

VSS7

nPULSE1
nPULSE2
nP1BAK

VDD5

nCKOEN

nRST

VSS6

nBJA
nBJB
nBJE
nMBA
nMBB
nMBE
nEXTOD

TMC2005-JT

TXENB1

HM

SE

NC

LE

EXTRX

ME

VSS1

EXTTX

VDD1

CKO

VSS2

CKM2
CKM1
CKM0

1
2
3
4
5
6
7
8
9

10
11
12
13
14
15

46

17 18 19 20 21 22 23 24 25 26 27 28 29 30

47

48

33

34

35

36

37

38

39

40

41

42

43

44

45

64 63 62

49

50

51

52

53

54

55

56

57

58

59

60

NC

16

NC

31

NC

32

NC

61

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SMSC TMC2005-JT 

Page 5  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

BLOCK DIAGRAM 

 
 
 

Direction Control

Circuit

OR

Circuit

OR

Circuit

OR

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

Rx

Buffer

Output

Control

Circuit

Tx

Pulse

Gen.

DPLL

AND

Circuit

Clock Multiplier

PLL

TXENA0

TXENA1

TXENB0
TXENB1

EXTTX

nP1BAK

nPULSE1

nPULSE2

VSS1- 8

VDD1- 6

CKO

nCKOEN

RO

LP

AVSS

nPLLTST

CKM2

CKM1

CKM0

nRST

AVSS

AVDD

XTLI

XTLO

RXFLT

EXTRX

RXINB1

RXINB0

RXINA1

RXINA0

SE SB SA

nBJE

nBJB

nBJA

nMBE

nMBB

nMBA

ME

MB

MA

LE

LB

LA

nEXTOD

HM

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

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Page 6 

SMSC TMC2005-JT 

 

DATASHEET

 

 

DESCRIPTION OF PIN FUNCTIONS 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

1  

TXENB1 

OUTPUT 

Port B-1 Tx output to media transceiver 

  

2  

HM 

INPUT 

Setting for traffic release time (It should 
be open for normal operation.) 

Pull-up 

3  

SE 

INPUT 

Port EXT. Polar assignment for EXTRX 
input (0:active Hi, 1:active Low) 

Pull-up 

4  

NC 

  

Reserved. It should be open. 

  

5  

LE 

INPUT 

Port EXT. Polar assignment of EXTTX 
output (0:active Low, 1:active Hi) 

Pull-up 

6  

EXTRX 

INPUT 

Port EXT. RX-Data input from media 
transceiver. Pull-up 

7  

ME 

INPUT 

Port EXT. Output mode assignment of 
EXTTX (0:pulse output, 1:Tx control 
output) Pull-up 

8  

VSS1 

  

Ground 

  

9  

EXTTX 

OUTPUT 

Port EXT. Output to media transceiver. 

  

10  

VDD1 

  

Power Supply 

  

11  

CKO 

OUTPUT 

Clock Output 

  

12  

VSS2 

  

Ground 

  

13  

CKM2 

INPUT 

Network speed (data rate) setting. 

Pull-up 

14  

CKM1 

INPUT 

  

Pull-up 

15  

CKM0 

INPUT 

  

Pull-up 

16  

NC 

  

Reserved. It should be open. 

  

17  

RXFLT 

INPUT 

Test Pin. It should be open. 

Pull-up 

18  

nPLLTST 

INPUT 

Test Pin for PLL.. It should connected to 
VDD (Set to high) 

  

19  

VDD2 

  

Power Supply 

  

20  

XTLI 

INPUT 

X'tal input/External clock input. 

  

21  

XTLO 

OUTPUT 

X'tal output 

  

22  

VSS4 

  

Ground 

  

23  

NC 

  

Reserved. It should be open. 

  

24  

VDD4 

  

Power Supply 

  

25  

VDD3 

  

Power Supply 

  

26  

AVDD 

  

Analog Power Supply 

  

27  

RO 

OUTPUT 

VCO output for internal PLL. 

  

28  

LP 

OUTPUT 

Connection pin to loop filter for internal 
PLL.  

 

29  

AGS 

INPUT 

Analog sense pin for internal PLL. 

  

30  

AVSS 

  

Analog Ground 

  

31  

VSS3 

  

Ground 

  

32  

VSS5 

  

Ground 

  

33  

NC 

  

Reserved. It should be open. 

  

34  

nEXTOD 

INPUT 

Port EXT. Open-drain mode (0:open-
drain output, 1:normal output) 

Pull-up 

35  

nMBE 

INPUT 

Port EXT. Noise cut (0:on, 1:off) 

Pull-up 

36  

nMBB 

INPUT 

Port A0/A1 Noise cut (0:on, 1:off) 

Pull-up 

37  

nMBA 

INPUT 

Port B0/B1 Noise cut (0:on, 1:off) 

Pull-up 

38  

nBJE 

INPUT 

Port EXT. Jitters correct mode (0:big 
jitters mode, 1:normal mode) 

Pull-up 

39  

nBJB 

INPUT 

Port A0/A1 Jitters correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

40  

nBJA 

INPUT 

Port B0/B1 Jitter correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

41  

VSS6 

  

Ground 

  

42  

nRST 

INPUT 

Internal reset signal (active Low) 

Pull-up 

43  

nCKOEN 

INPUT 

Enable of CKO output. 

Pull-up 

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ARCNET 5 Port HUB Controller 

 
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SMSC TMC2005-JT 

Page 7  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

44  

VDD5 

  

Power Supply. 

  

45  

nP1BAK 

OUTPUT 

nPULSE1 output (for backplane mode). 

  

46  

nPULSE2 

OUTPUT 

nPULSE2 output (for normal mode). 

  

47  

nPULSE1 

OUTPUT 

nPULSE1 output (for normal mode) 

  

48  

VSS7 

  

Ground 

  

49  

RXINA0 

INPUT 

Port A-0 Rx-data input from media 
transceiver. Pull-up 

50  

SA 

INPUT 

Port A. Polar assignment for RXINA0/A1 
output (0:active Hi, 1:active Low) 

Pull-up 

51  

TXENA0 

OUTPUT 

Port A-0 Tx output to media transceiver. 

  

52  

LA 

INPUT 

Port A. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

53  

RXINA1 

INPUT 

Port A-1 Rx-data input from media 
transceiver. Pull-up 

54  

MA 

INPUT 

Port A. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:Tx control 
output) Pull-up 

55  

TXENA1 

OUTPUT 

Port A-1 Tx output to media transceiver. 

  

56  

VDD6 

  

Power Supply 

  

57  

NC 

  

Reserved. It should be open. 

  

58  

VSS8 

  

Ground 

  

59  

RXINB0 

INPUT 

Port B-0 Rx-data input from media 
transceiver. Pull-up 

60  

SB 

INPUT 

Port B. Polar assignment for RXINA0/A1 
input (0:active Hi, 1:Active Low) 

Pull-up 

61  

TXENB0 

OUTPUT 

Port B-0 Tx output to media transceiver. 

  

62  

LB 

INPUT 

Port B. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

63  

RXINB1 

INPUT 

Port B-1 Rx-data input from media 
transceiver. Pull-up 

64  

MB 

INPUT 

Port B. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:TX control 
output) Pull-up 

 

Note: 

Pull-up: Input with a pull-up resistor 70KΩ ± 30% 

 
 

TX/RX Interface 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

RX Port 

 

RXINA [0:1] 
RXINB [0:1] 

EXTRX 

INPUT 

Setup the polarity by SA, SB, SE. 

RX Port 

Polar 

Assignment 

SA, SB, SE 

INPUT 

Setup the polarity of RXINA [0:1], 
RXINB [0:1], EXTTX. 
0 : active H 
1: active L 

TX Port 

TX Control 

TXENA [0:1] 
TXENB [0:1] 
EXTTX 

OUTPUT 

TX  data pulse  (Mx=0) or TX 
enable signal (Mx=1). 
Setup TX mode by MA, MB, ME. 
Setup the polarity by LA, LB, LE 

TX Port 

TX Data 

Output 

nPULSE [1:2] 

OUTPUT 

TX pulse data into HYC9068S-
SK/9088S-SK when ARCNET 
chip is at normal mode. 
The pulse is always active Low. 

TX Port 

 

nP1BAK 

OUTPUT 

TX pulse data into RS485 driver 
or HYC2485S/2488S when 
ARCNET chip is at backplane 

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Page 8 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

mode. 
The pulse is always active Low. 

TX Port 

Polarity 

Setup 

LA, LB, LE 

INPUT 

Setup the polarity of TXENA 
[0:1], TXENB [0:1], EXTTX. 
0 : active L 
1: active H 

TX Port 

Mode Setup 

MA, MB, ME 

INPUT 

Setup the mode of TXENA [0:1], 
TXENB [0:1], EXTTX. 
0: Output TX pulse. (It is 
equivalent to nTXEN “OR” 
nP1BAK) 
1: Output TX enable 

 
 
Operating Mode Setup

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

Data rate 
setup 

CKM [0:2] 

INPUT 

Terminal to setup the data rate of TMC2005. 
 
CKM2 CKM1 CKM0 DIVISOR  MULTIPLIER     SPEED 
   0       0         0       16            x1          156.25 Kbps 
   0       0         1        8             x1            312.5 Kbps 
   0       1         0        4             x1               625 Kbps 
   0       1         1        2             x1              1.25 Mbps 
   1       0         0        1             x1                2.5 Mbps 
   1       0         1        1             x2                   5 Mbps 
   1       1         0    Reserved    Reserved         Reserved 
   1       1         1        1             x4                 10 Mbps 
 
  External clock is 20MHz. 
  Refer to “VARIOUS SETUP” 

Noise cut 
mode 

nMBA 
nMBB 
nMBE 

INPUT 

0: Cut off noise from received data 
1: Don’t cut off noise 
 
Setup “0” normally. 

Big jitter 
mode 

nBJA 
nBJB 
nBJE 

INPUT 

Setup a jitter filter feature. 
Select a pulse as reference phase used by DPLL. 
 
0: 2

nd

 pulse (big jitter mode) 

1: 1

st

 pulse (normal mode) 

Open drain 
mode 

nEXTOD 

INPUT 

Setup a the use of EXTTX port. 
 
0: Set EXTTX as open drain output and use as Ext. 
1: Set EXTTX as normal output and use as 5

th

 port. 

 
PLL

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 LP 

OUTPUT 

Using PLL: Connect to an external condenser 
“C1” for loop filter. 

Using no PLL: must be open. 

 RO 

OUTPUT 

VCO 

output 

Using PLL: Connect to an external resistor “R0” for 
loop filter. 
Using no PLL: must be open. 

 

AGS 

INPUT 

Analog sense input. 
 
Using PLL: Connect to loop filter. 
Using no PLL: Connect to ground. 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 9  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 

nPLLTST 

INPUT 

Test pin for PLL. 
Must always connect to VDD. 

 

AVDD 

 

Analog power supply 
 
Using PLL: Analog power supply. There are some 
limits on PCB pattern. 
Using no PLL: Power supply (+5V) same as VDD1~6. 

 AVSS 

 

Analog 

ground 

 
Using PLL: Analog ground. There are some limits on 
PCB pattern. 
Using no PLL: Use a ground same as VSS1~8. 

 

Other Signals 

 

 

FEATURES 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

CRYSTAL 
INTERFACE 

XTLI 

INPUT 

Connect a 20MHz crystal. 
 
When supplying an external clock, 
input the clock to this pin. 

CRYSTAL 
INTERFACE 

XTLO 

OUTPUT 

Connect a 20MHz crystal. 
When supplying an external clock, it 
must be open. 

SYSTEM RESET 
INTERFACE 

nRST 

INPUT 

Reset for initializing TMC2005. (active 
Low) 

TEST PIN 

CKO 

OUTPUT 

Output internal clock of TMC2005. 

TEST PIN 

nCKOEN 

INPUT 

Output control of CKO. 
0: Output internal clock on CKO. 
1: Always output Low level on CKO. 
Set “1” Normally. 

TEST PIN 

RXFLT 

INPUT 

It must be open 

TEST PIN 

NC [1:2] 

 

It must be open 

POWER SUPPLY 

VDD [1:6] 

 

Power supply (+5V) 

GROUND VSS 

[1:8] 

 

Ground 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 10 

SMSC TMC2005-JT 

 

DATASHEET

 

 

OPERATIONAL DESCRIPTION 

 
Direction Determination

 

All TX ports are set to disable mode in the initial state. When a signal is received from any RX ports, the circuit holds 
the port on receiving mode (disable TX) and changes the other ports to sending mode (disable RX). One port stays in 
RX and the rest change into TX after all. The circuit initializes the internal DPLL on the timing of received RX pulse, 
and the RX buffer circuit stores the RX data and filters its jitter. TX controlling circuit regenerates the stored RX pulse 
on nPULSE1, nPULSE2 and nP1BAK. The nPULSE1 and nPULSE2 are pulse output pins for transceivers 
(HYC9088A) of ARCNET normal mode. The nP1BAK is a pulse output pin for transceiver (HYC5000/4000/2000 and 
RS485 driver) of ARCNET back plane mode. When using optical transceiver, instead of these signals, TXENA [0:1], 
TXENB [0:1], EXTTX (MA, MB, ME = 0) must be used as TX data inputs of the optical transceiver. 
 
Direction Release

 

On ARCNET protocol, each TX message starts with 6-bits of “1” ALERT and each data byte is lead by three bits (1, 1, 
0) preamble. To control the HUBs direction, the circuit monitors this bit pattern and holds the state. If the end of the bit 
pattern comes, all TX ports return receiving mode (disable TX) again. The interval timer detects the end of the bit 
pattern. During data is on line, silent period is less than 4 uS* because at least one bit “1” among 10-bits is received 
while receiving the data. The minimum silent interval from the end of received data to the alert of the next data (the 
minimum time of changing the direction) is the chip turn around time (12.6 uS*) of ARCNET controller. The interval 
timer to detect the data end is set to 5.6uS by adding some margin to the above interval for neglecting the reflection 
on a cable. 
[Note] Numbers marked * are at 2.5Mbps operation. 
 
Jitter Filter

 

To build a network with transceivers that introduce big jitter like ones for optical fiber, the old HUB that has direction 
control only may cause a transmission error because jitters on each HUB are added when several HUBs were 
connected in serial. The TMC2005 fixes that problem with jitter filtering and wave shaping through the following three 
steps. 
 
1) Input 

Sampling 

The TMC2005 samples a data on a network by eight times clock of the network data. 
 
2)  Jitter Filtering (DPLL) 
The TMC2005 filters the jitter (± 100nS at 2.5Mbps) of network data sampled by 8X clock through the internal digital 
PLL and stores the data into the buffer. 
 
3)  Wave Shaping Output 
The TMC2005 re-synchronizes and regenerates the network data at the same clock as the data rate.  
 
The capability of the jitter filtering is shown below. 
 

DATA RATE 

CAPABILITY OF JITTER FILTERING 

10Mbps ± 

25nS 

5Mbps ± 

50nS 

2.5Mbps ± 

100nS 

1.25Mbps ± 

200nS 

625Kbps ± 

400nS 

312.5Kbps ± 

800nS 

156.25Kbps ± 

1.6uS 

 

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SMSC TMC2005-JT 

 

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TMC2005-JT 

 

 

 
 
 
 
 

ARCNET 5 Port HUB Controller  

 

FEATURES 

 

ƒ

 

ARCNET HUB Circuit for ARCNET Protocol 
(Data Rate From 156.25Kbps to 10Mbps) 

ƒ

 

Able to Connect Various Transceivers Directly 

ƒ

 

Device Includes TX/RX Timing Circuit for 5 Port 
Hub and Direction Control Circuit, Jitter Correct 
Circuit and Noise Cancel Circuit 

ƒ

 

Easy to Design 8 or 12 Port Hub 

 

ƒ

 

Can Connect with HYC9088 in Normal Mode 

ƒ

 

Can Connect with RS485 Transceiver, 
HYC5000/4000/2000, Opt Module and TTL 
Interface in Backplane Mode 

ƒ

 

Supports both Normal and Backplane Mode at 
the Same Time for Media Conversion 

ƒ

 

+ 5V Single Power

 

 

GENERAL DESCRIPTION

 

 
When configuring a network, the maximum number of nodes and the maximum cable length are limited by the electric 
capacity of the transceiver. In this case, the network is expanded by an equipment called a “HUB” or “repeater”.  It 
maybe necessary to have a converter between coax, T/P and the fiber cable. It is easy to design a HUB or a repeater 
because the TMC2005 has various features for expanding such network. 
 
It can connect with HYC9088, RS485 transceiver, HYC5000/4000/2000 and TTL interface for optical module. It can 
connect with three different transceivers at the same time and convert the media of each. (The data rate cannot be 
converted. It is necessary to operate all nodes in the same network at the same data rate). The Hubs can be 
expanded by connecting two or more TMC2005 chips. By setting one of 5 ports to open-drain output, the Hub can be 
expanded to either 12 or 16 ports. 

 
 
 
 
 
 

 

ORDERING INFORMATION 

Order Number(s): 

 

TMC2005-JT for 64 pin, TQFP Lead-Free RoHS Compliant Package 

 

 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 2 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

   

80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123 

 
 

Copyright © 2007 SMSC or its subsidiaries. All rights reserved. 

 
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete 
information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no 
responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without 
notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information 
does not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of 
SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's 
standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or 
errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon 
request. SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure 
could cause or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC 
and further testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms 
of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems 
Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.  
 
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES 
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND 
ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY 
DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR 
REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC 
OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD TO 
HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 
DAMAGES. 
 
 
 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 3  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TABLE OF CONTENTS

 

FEATURES..................................................................................................................................................................1

 

GENERAL DESCRIPTION.......................................................................................................................................1

 

PIN CONFIGURATION ............................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................6

 

TX/RX

 

I

NTERFACE

....................................................................................................................................................7

 

O

PERATING 

M

ODE 

S

ETUP

..........................................................................................................................................8

 

PLL ...........................................................................................................................................................................8

 

O

THER 

S

IGNALS

........................................................................................................................................................9

 

OPERATIONAL DESCRIPTION...........................................................................................................................10

 

D

IRECTION 

D

ETERMINATION

...................................................................................................................................10

 

D

IRECTION 

R

ELEASE

...............................................................................................................................................10

 

J

ITTER 

F

ILTER

..........................................................................................................................................................10

 

O

PTION 

F

EATURE FOR 

J

ITTER 

F

ILTERING

.................................................................................................................11

 

O

PTION 

F

EATURE FOR 

N

OISE 

C

UT MODE

.................................................................................................................11

 

APPLICATION

 

NOTES ........................................................................................................................................12

 

PORT GROUP...........................................................................................................................................................20

 

V

ARIOUS 

S

ETUP

.......................................................................................................................................................20

 

E

XAMPLE 

F

OR 

O

PERATION 

M

ODE 

S

ETUP 

T

E

ACH 

P

ORT

........................................................................................20

 

N

OTE FOR 

U

NUSED PORT

.........................................................................................................................................20

 

E

XAMPLE FOR 

P

OWER

-O

R

ESET 

C

IRCUIT

..............................................................................................................20

 

CONNECTING THE TMC2005 WITH INTERNAL PLL...................................................................................21

 

M

ETHOD 

T

C

ONNECT 

A

 

C

RYSTAL 

C

LOCK

.............................................................................................................22

 

N

PLLTST

 PIN

..........................................................................................................................................................22

 

CASCADING CONNECTION ................................................................................................................................23

 

R

ING 

N

ETWORK 

W

ITH THE 

TMC2005.....................................................................................................................26

 

MAXIMUM

 

GUARANTEED

 

RATINGS*............................................................................................................27

 

STANDARD

 

OPERATING

 

CONDITION ............................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

INPUT

 

PIN ..................................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

OUTPUT

 

PIN ..............................................................................................................28

 

AC

 

CHARACTERISTIC

 

-

 

CLOCK

 AND 

RESET ...................................................................................................28

 

AC

 

CHARACTERISTIC

 

 

R

X WAVEFORMS AND 

T

X WAVEFORMS

........................................................................29

 

TMC2005-JT 64 PIN TQFP PACKAGE OUTLINE .............................................................................................31

 

 
 
 
 
 
 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 4 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 

PIN CONFIGURATION 

 

 
 

RX

IN

A

0

SA

TX

E

N

A

0

LA

MA

RX

IN

A

1

TX

E

N

A

1

VD

D

6

VSS

8

RX

IN

B

0

SB

TX

E

N

B

0

LB

MB

RX

IN

B

1

VS

S5

VS

S3

AV

SS

AGS

LP

AV

D

D

VD

D

3

VD

D

4

VS

S4

XT

LO

XT

L

I

VD

D

2

nPL

L

T

S

T

RX

FL

T

R0

VSS7

nPULSE1
nPULSE2
nP1BAK

VDD5

nCKOEN

nRST

VSS6

nBJA
nBJB
nBJE
nMBA
nMBB
nMBE
nEXTOD

TMC2005-JT

TXENB1

HM

SE

NC

LE

EXTRX

ME

VSS1

EXTTX

VDD1

CKO

VSS2

CKM2
CKM1
CKM0

1
2
3
4
5
6
7
8
9

10
11
12
13
14
15

46

17 18 19 20 21 22 23 24 25 26 27 28 29 30

47

48

33

34

35

36

37

38

39

40

41

42

43

44

45

64 63 62

49

50

51

52

53

54

55

56

57

58

59

60

NC

16

NC

31

NC

32

NC

61

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 5  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

BLOCK DIAGRAM 

 
 
 

Direction Control

Circuit

OR

Circuit

OR

Circuit

OR

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

Rx

Buffer

Output

Control

Circuit

Tx

Pulse

Gen.

DPLL

AND

Circuit

Clock Multiplier

PLL

TXENA0

TXENA1

TXENB0
TXENB1

EXTTX

nP1BAK

nPULSE1

nPULSE2

VSS1- 8

VDD1- 6

CKO

nCKOEN

RO

LP

AVSS

nPLLTST

CKM2

CKM1

CKM0

nRST

AVSS

AVDD

XTLI

XTLO

RXFLT

EXTRX

RXINB1

RXINB0

RXINA1

RXINA0

SE SB SA

nBJE

nBJB

nBJA

nMBE

nMBB

nMBA

ME

MB

MA

LE

LB

LA

nEXTOD

HM

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 6 

SMSC TMC2005-JT 

 

DATASHEET

 

 

DESCRIPTION OF PIN FUNCTIONS 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

1  

TXENB1 

OUTPUT 

Port B-1 Tx output to media transceiver 

  

2  

HM 

INPUT 

Setting for traffic release time (It should 
be open for normal operation.) 

Pull-up 

3  

SE 

INPUT 

Port EXT. Polar assignment for EXTRX 
input (0:active Hi, 1:active Low) 

Pull-up 

4  

NC 

  

Reserved. It should be open. 

  

5  

LE 

INPUT 

Port EXT. Polar assignment of EXTTX 
output (0:active Low, 1:active Hi) 

Pull-up 

6  

EXTRX 

INPUT 

Port EXT. RX-Data input from media 
transceiver. Pull-up 

7  

ME 

INPUT 

Port EXT. Output mode assignment of 
EXTTX (0:pulse output, 1:Tx control 
output) Pull-up 

8  

VSS1 

  

Ground 

  

9  

EXTTX 

OUTPUT 

Port EXT. Output to media transceiver. 

  

10  

VDD1 

  

Power Supply 

  

11  

CKO 

OUTPUT 

Clock Output 

  

12  

VSS2 

  

Ground 

  

13  

CKM2 

INPUT 

Network speed (data rate) setting. 

Pull-up 

14  

CKM1 

INPUT 

  

Pull-up 

15  

CKM0 

INPUT 

  

Pull-up 

16  

NC 

  

Reserved. It should be open. 

  

17  

RXFLT 

INPUT 

Test Pin. It should be open. 

Pull-up 

18  

nPLLTST 

INPUT 

Test Pin for PLL.. It should connected to 
VDD (Set to high) 

  

19  

VDD2 

  

Power Supply 

  

20  

XTLI 

INPUT 

X'tal input/External clock input. 

  

21  

XTLO 

OUTPUT 

X'tal output 

  

22  

VSS4 

  

Ground 

  

23  

NC 

  

Reserved. It should be open. 

  

24  

VDD4 

  

Power Supply 

  

25  

VDD3 

  

Power Supply 

  

26  

AVDD 

  

Analog Power Supply 

  

27  

RO 

OUTPUT 

VCO output for internal PLL. 

  

28  

LP 

OUTPUT 

Connection pin to loop filter for internal 
PLL.  

 

29  

AGS 

INPUT 

Analog sense pin for internal PLL. 

  

30  

AVSS 

  

Analog Ground 

  

31  

VSS3 

  

Ground 

  

32  

VSS5 

  

Ground 

  

33  

NC 

  

Reserved. It should be open. 

  

34  

nEXTOD 

INPUT 

Port EXT. Open-drain mode (0:open-
drain output, 1:normal output) 

Pull-up 

35  

nMBE 

INPUT 

Port EXT. Noise cut (0:on, 1:off) 

Pull-up 

36  

nMBB 

INPUT 

Port A0/A1 Noise cut (0:on, 1:off) 

Pull-up 

37  

nMBA 

INPUT 

Port B0/B1 Noise cut (0:on, 1:off) 

Pull-up 

38  

nBJE 

INPUT 

Port EXT. Jitters correct mode (0:big 
jitters mode, 1:normal mode) 

Pull-up 

39  

nBJB 

INPUT 

Port A0/A1 Jitters correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

40  

nBJA 

INPUT 

Port B0/B1 Jitter correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

41  

VSS6 

  

Ground 

  

42  

nRST 

INPUT 

Internal reset signal (active Low) 

Pull-up 

43  

nCKOEN 

INPUT 

Enable of CKO output. 

Pull-up 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 7  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

44  

VDD5 

  

Power Supply. 

  

45  

nP1BAK 

OUTPUT 

nPULSE1 output (for backplane mode). 

  

46  

nPULSE2 

OUTPUT 

nPULSE2 output (for normal mode). 

  

47  

nPULSE1 

OUTPUT 

nPULSE1 output (for normal mode) 

  

48  

VSS7 

  

Ground 

  

49  

RXINA0 

INPUT 

Port A-0 Rx-data input from media 
transceiver. Pull-up 

50  

SA 

INPUT 

Port A. Polar assignment for RXINA0/A1 
output (0:active Hi, 1:active Low) 

Pull-up 

51  

TXENA0 

OUTPUT 

Port A-0 Tx output to media transceiver. 

  

52  

LA 

INPUT 

Port A. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

53  

RXINA1 

INPUT 

Port A-1 Rx-data input from media 
transceiver. Pull-up 

54  

MA 

INPUT 

Port A. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:Tx control 
output) Pull-up 

55  

TXENA1 

OUTPUT 

Port A-1 Tx output to media transceiver. 

  

56  

VDD6 

  

Power Supply 

  

57  

NC 

  

Reserved. It should be open. 

  

58  

VSS8 

  

Ground 

  

59  

RXINB0 

INPUT 

Port B-0 Rx-data input from media 
transceiver. Pull-up 

60  

SB 

INPUT 

Port B. Polar assignment for RXINA0/A1 
input (0:active Hi, 1:Active Low) 

Pull-up 

61  

TXENB0 

OUTPUT 

Port B-0 Tx output to media transceiver. 

  

62  

LB 

INPUT 

Port B. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

63  

RXINB1 

INPUT 

Port B-1 Rx-data input from media 
transceiver. Pull-up 

64  

MB 

INPUT 

Port B. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:TX control 
output) Pull-up 

 

Note: 

Pull-up: Input with a pull-up resistor 70KΩ ± 30% 

 
 

TX/RX Interface 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

RX Port 

 

RXINA [0:1] 
RXINB [0:1] 

EXTRX 

INPUT 

Setup the polarity by SA, SB, SE. 

RX Port 

Polar 

Assignment 

SA, SB, SE 

INPUT 

Setup the polarity of RXINA [0:1], 
RXINB [0:1], EXTTX. 
0 : active H 
1: active L 

TX Port 

TX Control 

TXENA [0:1] 
TXENB [0:1] 
EXTTX 

OUTPUT 

TX  data pulse  (Mx=0) or TX 
enable signal (Mx=1). 
Setup TX mode by MA, MB, ME. 
Setup the polarity by LA, LB, LE 

TX Port 

TX Data 

Output 

nPULSE [1:2] 

OUTPUT 

TX pulse data into HYC9068S-
SK/9088S-SK when ARCNET 
chip is at normal mode. 
The pulse is always active Low. 

TX Port 

 

nP1BAK 

OUTPUT 

TX pulse data into RS485 driver 
or HYC2485S/2488S when 
ARCNET chip is at backplane 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

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Page 8 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

mode. 
The pulse is always active Low. 

TX Port 

Polarity 

Setup 

LA, LB, LE 

INPUT 

Setup the polarity of TXENA 
[0:1], TXENB [0:1], EXTTX. 
0 : active L 
1: active H 

TX Port 

Mode Setup 

MA, MB, ME 

INPUT 

Setup the mode of TXENA [0:1], 
TXENB [0:1], EXTTX. 
0: Output TX pulse. (It is 
equivalent to nTXEN “OR” 
nP1BAK) 
1: Output TX enable 

 
 
Operating Mode Setup

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

Data rate 
setup 

CKM [0:2] 

INPUT 

Terminal to setup the data rate of TMC2005. 
 
CKM2 CKM1 CKM0 DIVISOR  MULTIPLIER     SPEED 
   0       0         0       16            x1          156.25 Kbps 
   0       0         1        8             x1            312.5 Kbps 
   0       1         0        4             x1               625 Kbps 
   0       1         1        2             x1              1.25 Mbps 
   1       0         0        1             x1                2.5 Mbps 
   1       0         1        1             x2                   5 Mbps 
   1       1         0    Reserved    Reserved         Reserved 
   1       1         1        1             x4                 10 Mbps 
 
  External clock is 20MHz. 
  Refer to “VARIOUS SETUP” 

Noise cut 
mode 

nMBA 
nMBB 
nMBE 

INPUT 

0: Cut off noise from received data 
1: Don’t cut off noise 
 
Setup “0” normally. 

Big jitter 
mode 

nBJA 
nBJB 
nBJE 

INPUT 

Setup a jitter filter feature. 
Select a pulse as reference phase used by DPLL. 
 
0: 2

nd

 pulse (big jitter mode) 

1: 1

st

 pulse (normal mode) 

Open drain 
mode 

nEXTOD 

INPUT 

Setup a the use of EXTTX port. 
 
0: Set EXTTX as open drain output and use as Ext. 
1: Set EXTTX as normal output and use as 5

th

 port. 

 
PLL

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 LP 

OUTPUT 

Using PLL: Connect to an external condenser 
“C1” for loop filter. 

Using no PLL: must be open. 

 RO 

OUTPUT 

VCO 

output 

Using PLL: Connect to an external resistor “R0” for 
loop filter. 
Using no PLL: must be open. 

 

AGS 

INPUT 

Analog sense input. 
 
Using PLL: Connect to loop filter. 
Using no PLL: Connect to ground. 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 9  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 

nPLLTST 

INPUT 

Test pin for PLL. 
Must always connect to VDD. 

 

AVDD 

 

Analog power supply 
 
Using PLL: Analog power supply. There are some 
limits on PCB pattern. 
Using no PLL: Power supply (+5V) same as VDD1~6. 

 AVSS 

 

Analog 

ground 

 
Using PLL: Analog ground. There are some limits on 
PCB pattern. 
Using no PLL: Use a ground same as VSS1~8. 

 

Other Signals 

 

 

FEATURES 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

CRYSTAL 
INTERFACE 

XTLI 

INPUT 

Connect a 20MHz crystal. 
 
When supplying an external clock, 
input the clock to this pin. 

CRYSTAL 
INTERFACE 

XTLO 

OUTPUT 

Connect a 20MHz crystal. 
When supplying an external clock, it 
must be open. 

SYSTEM RESET 
INTERFACE 

nRST 

INPUT 

Reset for initializing TMC2005. (active 
Low) 

TEST PIN 

CKO 

OUTPUT 

Output internal clock of TMC2005. 

TEST PIN 

nCKOEN 

INPUT 

Output control of CKO. 
0: Output internal clock on CKO. 
1: Always output Low level on CKO. 
Set “1” Normally. 

TEST PIN 

RXFLT 

INPUT 

It must be open 

TEST PIN 

NC [1:2] 

 

It must be open 

POWER SUPPLY 

VDD [1:6] 

 

Power supply (+5V) 

GROUND VSS 

[1:8] 

 

Ground 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 10 

SMSC TMC2005-JT 

 

DATASHEET

 

 

OPERATIONAL DESCRIPTION 

 
Direction Determination

 

All TX ports are set to disable mode in the initial state. When a signal is received from any RX ports, the circuit holds 
the port on receiving mode (disable TX) and changes the other ports to sending mode (disable RX). One port stays in 
RX and the rest change into TX after all. The circuit initializes the internal DPLL on the timing of received RX pulse, 
and the RX buffer circuit stores the RX data and filters its jitter. TX controlling circuit regenerates the stored RX pulse 
on nPULSE1, nPULSE2 and nP1BAK. The nPULSE1 and nPULSE2 are pulse output pins for transceivers 
(HYC9088A) of ARCNET normal mode. The nP1BAK is a pulse output pin for transceiver (HYC5000/4000/2000 and 
RS485 driver) of ARCNET back plane mode. When using optical transceiver, instead of these signals, TXENA [0:1], 
TXENB [0:1], EXTTX (MA, MB, ME = 0) must be used as TX data inputs of the optical transceiver. 
 
Direction Release

 

On ARCNET protocol, each TX message starts with 6-bits of “1” ALERT and each data byte is lead by three bits (1, 1, 
0) preamble. To control the HUBs direction, the circuit monitors this bit pattern and holds the state. If the end of the bit 
pattern comes, all TX ports return receiving mode (disable TX) again. The interval timer detects the end of the bit 
pattern. During data is on line, silent period is less than 4 uS* because at least one bit “1” among 10-bits is received 
while receiving the data. The minimum silent interval from the end of received data to the alert of the next data (the 
minimum time of changing the direction) is the chip turn around time (12.6 uS*) of ARCNET controller. The interval 
timer to detect the data end is set to 5.6uS by adding some margin to the above interval for neglecting the reflection 
on a cable. 
[Note] Numbers marked * are at 2.5Mbps operation. 
 
Jitter Filter

 

To build a network with transceivers that introduce big jitter like ones for optical fiber, the old HUB that has direction 
control only may cause a transmission error because jitters on each HUB are added when several HUBs were 
connected in serial. The TMC2005 fixes that problem with jitter filtering and wave shaping through the following three 
steps. 
 
1) Input 

Sampling 

The TMC2005 samples a data on a network by eight times clock of the network data. 
 
2)  Jitter Filtering (DPLL) 
The TMC2005 filters the jitter (± 100nS at 2.5Mbps) of network data sampled by 8X clock through the internal digital 
PLL and stores the data into the buffer. 
 
3)  Wave Shaping Output 
The TMC2005 re-synchronizes and regenerates the network data at the same clock as the data rate.  
 
The capability of the jitter filtering is shown below. 
 

DATA RATE 

CAPABILITY OF JITTER FILTERING 

10Mbps ± 

25nS 

5Mbps ± 

50nS 

2.5Mbps ± 

100nS 

1.25Mbps ± 

200nS 

625Kbps ± 

400nS 

312.5Kbps ± 

800nS 

156.25Kbps ± 

1.6uS 

 

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SMSC TMC2005-JT 

 

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TMC2005-JT 

 

 

 
 
 
 
 

ARCNET 5 Port HUB Controller  

 

FEATURES 

 

ƒ

 

ARCNET HUB Circuit for ARCNET Protocol 
(Data Rate From 156.25Kbps to 10Mbps) 

ƒ

 

Able to Connect Various Transceivers Directly 

ƒ

 

Device Includes TX/RX Timing Circuit for 5 Port 
Hub and Direction Control Circuit, Jitter Correct 
Circuit and Noise Cancel Circuit 

ƒ

 

Easy to Design 8 or 12 Port Hub 

 

ƒ

 

Can Connect with HYC9088 in Normal Mode 

ƒ

 

Can Connect with RS485 Transceiver, 
HYC5000/4000/2000, Opt Module and TTL 
Interface in Backplane Mode 

ƒ

 

Supports both Normal and Backplane Mode at 
the Same Time for Media Conversion 

ƒ

 

+ 5V Single Power

 

 

GENERAL DESCRIPTION

 

 
When configuring a network, the maximum number of nodes and the maximum cable length are limited by the electric 
capacity of the transceiver. In this case, the network is expanded by an equipment called a “HUB” or “repeater”.  It 
maybe necessary to have a converter between coax, T/P and the fiber cable. It is easy to design a HUB or a repeater 
because the TMC2005 has various features for expanding such network. 
 
It can connect with HYC9088, RS485 transceiver, HYC5000/4000/2000 and TTL interface for optical module. It can 
connect with three different transceivers at the same time and convert the media of each. (The data rate cannot be 
converted. It is necessary to operate all nodes in the same network at the same data rate). The Hubs can be 
expanded by connecting two or more TMC2005 chips. By setting one of 5 ports to open-drain output, the Hub can be 
expanded to either 12 or 16 ports. 

 
 
 
 
 
 

 

ORDERING INFORMATION 

Order Number(s): 

 

TMC2005-JT for 64 pin, TQFP Lead-Free RoHS Compliant Package 

 

 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 2 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 

 

 

   

80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123 

 
 

Copyright © 2007 SMSC or its subsidiaries. All rights reserved. 

 
Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete 
information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no 
responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without 
notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information 
does not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of 
SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's 
standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or 
errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon 
request. SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure 
could cause or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC 
and further testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms 
of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems 
Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders.  
 
SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES 
OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND 
ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY 
DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR 
REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC 
OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD TO 
HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH 
DAMAGES. 
 
 
 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 3  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

TABLE OF CONTENTS

 

FEATURES..................................................................................................................................................................1

 

GENERAL DESCRIPTION.......................................................................................................................................1

 

PIN CONFIGURATION ............................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................4

 

BLOCK DIAGRAM....................................................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................5

 

DESCRIPTION OF PIN FUNCTIONS ....................................................................................................................6

 

TX/RX

 

I

NTERFACE

....................................................................................................................................................7

 

O

PERATING 

M

ODE 

S

ETUP

..........................................................................................................................................8

 

PLL ...........................................................................................................................................................................8

 

O

THER 

S

IGNALS

........................................................................................................................................................9

 

OPERATIONAL DESCRIPTION...........................................................................................................................10

 

D

IRECTION 

D

ETERMINATION

...................................................................................................................................10

 

D

IRECTION 

R

ELEASE

...............................................................................................................................................10

 

J

ITTER 

F

ILTER

..........................................................................................................................................................10

 

O

PTION 

F

EATURE FOR 

J

ITTER 

F

ILTERING

.................................................................................................................11

 

O

PTION 

F

EATURE FOR 

N

OISE 

C

UT MODE

.................................................................................................................11

 

APPLICATION

 

NOTES ........................................................................................................................................12

 

PORT GROUP...........................................................................................................................................................20

 

V

ARIOUS 

S

ETUP

.......................................................................................................................................................20

 

E

XAMPLE 

F

OR 

O

PERATION 

M

ODE 

S

ETUP 

T

E

ACH 

P

ORT

........................................................................................20

 

N

OTE FOR 

U

NUSED PORT

.........................................................................................................................................20

 

E

XAMPLE FOR 

P

OWER

-O

R

ESET 

C

IRCUIT

..............................................................................................................20

 

CONNECTING THE TMC2005 WITH INTERNAL PLL...................................................................................21

 

M

ETHOD 

T

C

ONNECT 

A

 

C

RYSTAL 

C

LOCK

.............................................................................................................22

 

N

PLLTST

 PIN

..........................................................................................................................................................22

 

CASCADING CONNECTION ................................................................................................................................23

 

R

ING 

N

ETWORK 

W

ITH THE 

TMC2005.....................................................................................................................26

 

MAXIMUM

 

GUARANTEED

 

RATINGS*............................................................................................................27

 

STANDARD

 

OPERATING

 

CONDITION ............................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

INPUT

 

PIN ..................................................................................................................27

 

DC

 

CHARACTERISTIC

 

-

 

OUTPUT

 

PIN ..............................................................................................................28

 

AC

 

CHARACTERISTIC

 

-

 

CLOCK

 AND 

RESET ...................................................................................................28

 

AC

 

CHARACTERISTIC

 

 

R

X WAVEFORMS AND 

T

X WAVEFORMS

........................................................................29

 

TMC2005-JT 64 PIN TQFP PACKAGE OUTLINE .............................................................................................31

 

 
 
 
 
 
 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 4 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 

PIN CONFIGURATION 

 

 
 

RX

IN

A

0

SA

TX

E

N

A

0

LA

MA

RX

IN

A

1

TX

E

N

A

1

VD

D

6

VSS

8

RX

IN

B

0

SB

TX

E

N

B

0

LB

MB

RX

IN

B

1

VS

S5

VS

S3

AV

SS

AGS

LP

AV

D

D

VD

D

3

VD

D

4

VS

S4

XT

LO

XT

L

I

VD

D

2

nPL

L

T

S

T

RX

FL

T

R0

VSS7

nPULSE1
nPULSE2
nP1BAK

VDD5

nCKOEN

nRST

VSS6

nBJA
nBJB
nBJE
nMBA
nMBB
nMBE
nEXTOD

TMC2005-JT

TXENB1

HM

SE

NC

LE

EXTRX

ME

VSS1

EXTTX

VDD1

CKO

VSS2

CKM2
CKM1
CKM0

1
2
3
4
5
6
7
8
9

10
11
12
13
14
15

46

17 18 19 20 21 22 23 24 25 26 27 28 29 30

47

48

33

34

35

36

37

38

39

40

41

42

43

44

45

64 63 62

49

50

51

52

53

54

55

56

57

58

59

60

NC

16

NC

31

NC

32

NC

61

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 5  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

BLOCK DIAGRAM 

 
 
 

Direction Control

Circuit

OR

Circuit

OR

Circuit

OR

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

NOT

Circuit

Rx

Buffer

Output

Control

Circuit

Tx

Pulse

Gen.

DPLL

AND

Circuit

Clock Multiplier

PLL

TXENA0

TXENA1

TXENB0
TXENB1

EXTTX

nP1BAK

nPULSE1

nPULSE2

VSS1- 8

VDD1- 6

CKO

nCKOEN

RO

LP

AVSS

nPLLTST

CKM2

CKM1

CKM0

nRST

AVSS

AVDD

XTLI

XTLO

RXFLT

EXTRX

RXINB1

RXINB0

RXINA1

RXINA0

SE SB SA

nBJE

nBJB

nBJA

nMBE

nMBB

nMBA

ME

MB

MA

LE

LB

LA

nEXTOD

HM

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 6 

SMSC TMC2005-JT 

 

DATASHEET

 

 

DESCRIPTION OF PIN FUNCTIONS 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

1  

TXENB1 

OUTPUT 

Port B-1 Tx output to media transceiver 

  

2  

HM 

INPUT 

Setting for traffic release time (It should 
be open for normal operation.) 

Pull-up 

3  

SE 

INPUT 

Port EXT. Polar assignment for EXTRX 
input (0:active Hi, 1:active Low) 

Pull-up 

4  

NC 

  

Reserved. It should be open. 

  

5  

LE 

INPUT 

Port EXT. Polar assignment of EXTTX 
output (0:active Low, 1:active Hi) 

Pull-up 

6  

EXTRX 

INPUT 

Port EXT. RX-Data input from media 
transceiver. Pull-up 

7  

ME 

INPUT 

Port EXT. Output mode assignment of 
EXTTX (0:pulse output, 1:Tx control 
output) Pull-up 

8  

VSS1 

  

Ground 

  

9  

EXTTX 

OUTPUT 

Port EXT. Output to media transceiver. 

  

10  

VDD1 

  

Power Supply 

  

11  

CKO 

OUTPUT 

Clock Output 

  

12  

VSS2 

  

Ground 

  

13  

CKM2 

INPUT 

Network speed (data rate) setting. 

Pull-up 

14  

CKM1 

INPUT 

  

Pull-up 

15  

CKM0 

INPUT 

  

Pull-up 

16  

NC 

  

Reserved. It should be open. 

  

17  

RXFLT 

INPUT 

Test Pin. It should be open. 

Pull-up 

18  

nPLLTST 

INPUT 

Test Pin for PLL.. It should connected to 
VDD (Set to high) 

  

19  

VDD2 

  

Power Supply 

  

20  

XTLI 

INPUT 

X'tal input/External clock input. 

  

21  

XTLO 

OUTPUT 

X'tal output 

  

22  

VSS4 

  

Ground 

  

23  

NC 

  

Reserved. It should be open. 

  

24  

VDD4 

  

Power Supply 

  

25  

VDD3 

  

Power Supply 

  

26  

AVDD 

  

Analog Power Supply 

  

27  

RO 

OUTPUT 

VCO output for internal PLL. 

  

28  

LP 

OUTPUT 

Connection pin to loop filter for internal 
PLL.  

 

29  

AGS 

INPUT 

Analog sense pin for internal PLL. 

  

30  

AVSS 

  

Analog Ground 

  

31  

VSS3 

  

Ground 

  

32  

VSS5 

  

Ground 

  

33  

NC 

  

Reserved. It should be open. 

  

34  

nEXTOD 

INPUT 

Port EXT. Open-drain mode (0:open-
drain output, 1:normal output) 

Pull-up 

35  

nMBE 

INPUT 

Port EXT. Noise cut (0:on, 1:off) 

Pull-up 

36  

nMBB 

INPUT 

Port A0/A1 Noise cut (0:on, 1:off) 

Pull-up 

37  

nMBA 

INPUT 

Port B0/B1 Noise cut (0:on, 1:off) 

Pull-up 

38  

nBJE 

INPUT 

Port EXT. Jitters correct mode (0:big 
jitters mode, 1:normal mode) 

Pull-up 

39  

nBJB 

INPUT 

Port A0/A1 Jitters correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

40  

nBJA 

INPUT 

Port B0/B1 Jitter correct mode (0:big 
jitter mode, 1:normal mode) 

Pull-up 

41  

VSS6 

  

Ground 

  

42  

nRST 

INPUT 

Internal reset signal (active Low) 

Pull-up 

43  

nCKOEN 

INPUT 

Enable of CKO output. 

Pull-up 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 7  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

PIN NO. 

NAME 

INPUT/OUTPUT 

DESCRIPTION 

NOTE 

44  

VDD5 

  

Power Supply. 

  

45  

nP1BAK 

OUTPUT 

nPULSE1 output (for backplane mode). 

  

46  

nPULSE2 

OUTPUT 

nPULSE2 output (for normal mode). 

  

47  

nPULSE1 

OUTPUT 

nPULSE1 output (for normal mode) 

  

48  

VSS7 

  

Ground 

  

49  

RXINA0 

INPUT 

Port A-0 Rx-data input from media 
transceiver. Pull-up 

50  

SA 

INPUT 

Port A. Polar assignment for RXINA0/A1 
output (0:active Hi, 1:active Low) 

Pull-up 

51  

TXENA0 

OUTPUT 

Port A-0 Tx output to media transceiver. 

  

52  

LA 

INPUT 

Port A. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

53  

RXINA1 

INPUT 

Port A-1 Rx-data input from media 
transceiver. Pull-up 

54  

MA 

INPUT 

Port A. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:Tx control 
output) Pull-up 

55  

TXENA1 

OUTPUT 

Port A-1 Tx output to media transceiver. 

  

56  

VDD6 

  

Power Supply 

  

57  

NC 

  

Reserved. It should be open. 

  

58  

VSS8 

  

Ground 

  

59  

RXINB0 

INPUT 

Port B-0 Rx-data input from media 
transceiver. Pull-up 

60  

SB 

INPUT 

Port B. Polar assignment for RXINA0/A1 
input (0:active Hi, 1:Active Low) 

Pull-up 

61  

TXENB0 

OUTPUT 

Port B-0 Tx output to media transceiver. 

  

62  

LB 

INPUT 

Port B. Polar assignment for TXENA0/A1 
output (0:active Low, 1:active Hi) 

Pull-up 

63  

RXINB1 

INPUT 

Port B-1 Rx-data input from media 
transceiver. Pull-up 

64  

MB 

INPUT 

Port B. Mode assignment for 
TXENA0/A1 (0:pulse output, 1:TX control 
output) Pull-up 

 

Note: 

Pull-up: Input with a pull-up resistor 70KΩ ± 30% 

 
 

TX/RX Interface 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

RX Port 

 

RXINA [0:1] 
RXINB [0:1] 

EXTRX 

INPUT 

Setup the polarity by SA, SB, SE. 

RX Port 

Polar 

Assignment 

SA, SB, SE 

INPUT 

Setup the polarity of RXINA [0:1], 
RXINB [0:1], EXTTX. 
0 : active H 
1: active L 

TX Port 

TX Control 

TXENA [0:1] 
TXENB [0:1] 
EXTTX 

OUTPUT 

TX  data pulse  (Mx=0) or TX 
enable signal (Mx=1). 
Setup TX mode by MA, MB, ME. 
Setup the polarity by LA, LB, LE 

TX Port 

TX Data 

Output 

nPULSE [1:2] 

OUTPUT 

TX pulse data into HYC9068S-
SK/9088S-SK when ARCNET 
chip is at normal mode. 
The pulse is always active Low. 

TX Port 

 

nP1BAK 

OUTPUT 

TX pulse data into RS485 driver 
or HYC2485S/2488S when 
ARCNET chip is at backplane 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 8 

SMSC TMC2005-JT 

 

DATASHEET

 

 

 FEATURE NAME 

INPUT/OUTPUT 

DESCRIPTION 

mode. 
The pulse is always active Low. 

TX Port 

Polarity 

Setup 

LA, LB, LE 

INPUT 

Setup the polarity of TXENA 
[0:1], TXENB [0:1], EXTTX. 
0 : active L 
1: active H 

TX Port 

Mode Setup 

MA, MB, ME 

INPUT 

Setup the mode of TXENA [0:1], 
TXENB [0:1], EXTTX. 
0: Output TX pulse. (It is 
equivalent to nTXEN “OR” 
nP1BAK) 
1: Output TX enable 

 
 
Operating Mode Setup

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

Data rate 
setup 

CKM [0:2] 

INPUT 

Terminal to setup the data rate of TMC2005. 
 
CKM2 CKM1 CKM0 DIVISOR  MULTIPLIER     SPEED 
   0       0         0       16            x1          156.25 Kbps 
   0       0         1        8             x1            312.5 Kbps 
   0       1         0        4             x1               625 Kbps 
   0       1         1        2             x1              1.25 Mbps 
   1       0         0        1             x1                2.5 Mbps 
   1       0         1        1             x2                   5 Mbps 
   1       1         0    Reserved    Reserved         Reserved 
   1       1         1        1             x4                 10 Mbps 
 
  External clock is 20MHz. 
  Refer to “VARIOUS SETUP” 

Noise cut 
mode 

nMBA 
nMBB 
nMBE 

INPUT 

0: Cut off noise from received data 
1: Don’t cut off noise 
 
Setup “0” normally. 

Big jitter 
mode 

nBJA 
nBJB 
nBJE 

INPUT 

Setup a jitter filter feature. 
Select a pulse as reference phase used by DPLL. 
 
0: 2

nd

 pulse (big jitter mode) 

1: 1

st

 pulse (normal mode) 

Open drain 
mode 

nEXTOD 

INPUT 

Setup a the use of EXTTX port. 
 
0: Set EXTTX as open drain output and use as Ext. 
1: Set EXTTX as normal output and use as 5

th

 port. 

 
PLL

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 LP 

OUTPUT 

Using PLL: Connect to an external condenser 
“C1” for loop filter. 

Using no PLL: must be open. 

 RO 

OUTPUT 

VCO 

output 

Using PLL: Connect to an external resistor “R0” for 
loop filter. 
Using no PLL: must be open. 

 

AGS 

INPUT 

Analog sense input. 
 
Using PLL: Connect to loop filter. 
Using no PLL: Connect to ground. 

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ARCNET 5 Port HUB Controller 

 
   Datasheet 

 

SMSC TMC2005-JT 

Page 9  

Revision 1.1 (07-24-07) 

 

DATASHEET

 

 

 

 

FEATURE 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

 

nPLLTST 

INPUT 

Test pin for PLL. 
Must always connect to VDD. 

 

AVDD 

 

Analog power supply 
 
Using PLL: Analog power supply. There are some 
limits on PCB pattern. 
Using no PLL: Power supply (+5V) same as VDD1~6. 

 AVSS 

 

Analog 

ground 

 
Using PLL: Analog ground. There are some limits on 
PCB pattern. 
Using no PLL: Use a ground same as VSS1~8. 

 

Other Signals 

 

 

FEATURES 

 

NAME 

INPUT/ 

OUTPUT 

 

DESCRIPTION 

CRYSTAL 
INTERFACE 

XTLI 

INPUT 

Connect a 20MHz crystal. 
 
When supplying an external clock, 
input the clock to this pin. 

CRYSTAL 
INTERFACE 

XTLO 

OUTPUT 

Connect a 20MHz crystal. 
When supplying an external clock, it 
must be open. 

SYSTEM RESET 
INTERFACE 

nRST 

INPUT 

Reset for initializing TMC2005. (active 
Low) 

TEST PIN 

CKO 

OUTPUT 

Output internal clock of TMC2005. 

TEST PIN 

nCKOEN 

INPUT 

Output control of CKO. 
0: Output internal clock on CKO. 
1: Always output Low level on CKO. 
Set “1” Normally. 

TEST PIN 

RXFLT 

INPUT 

It must be open 

TEST PIN 

NC [1:2] 

 

It must be open 

POWER SUPPLY 

VDD [1:6] 

 

Power supply (+5V) 

GROUND VSS 

[1:8] 

 

Ground 

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ARCNET 5 Port HUB Controller 
 
Datasheet 

 

Revision 1.1 (07-24-07) 

Page 10 

SMSC TMC2005-JT 

 

DATASHEET

 

 

OPERATIONAL DESCRIPTION 

 
Direction Determination

 

All TX ports are set to disable mode in the initial state. When a signal is received from any RX ports, the circuit holds 
the port on receiving mode (disable TX) and changes the other ports to sending mode (disable RX). One port stays in 
RX and the rest change into TX after all. The circuit initializes the internal DPLL on the timing of received RX pulse, 
and the RX buffer circuit stores the RX data and filters its jitter. TX controlling circuit regenerates the stored RX pulse 
on nPULSE1, nPULSE2 and nP1BAK. The nPULSE1 and nPULSE2 are pulse output pins for transceivers 
(HYC9088A) of ARCNET normal mode. The nP1BAK is a pulse output pin for transceiver (HYC5000/4000/2000 and 
RS485 driver) of ARCNET back plane mode. When using optical transceiver, instead of these signals, TXENA [0:1], 
TXENB [0:1], EXTTX (MA, MB, ME = 0) must be used as TX data inputs of the optical transceiver. 
 
Direction Release

 

On ARCNET protocol, each TX message starts with 6-bits of “1” ALERT and each data byte is lead by three bits (1, 1, 
0) preamble. To control the HUBs direction, the circuit monitors this bit pattern and holds the state. If the end of the bit 
pattern comes, all TX ports return receiving mode (disable TX) again. The interval timer detects the end of the bit 
pattern. During data is on line, silent period is less than 4 uS* because at least one bit “1” among 10-bits is received 
while receiving the data. The minimum silent interval from the end of received data to the alert of the next data (the 
minimum time of changing the direction) is the chip turn around time (12.6 uS*) of ARCNET controller. The interval 
timer to detect the data end is set to 5.6uS by adding some margin to the above interval for neglecting the reflection 
on a cable. 
[Note] Numbers marked * are at 2.5Mbps operation. 
 
Jitter Filter

 

To build a network with transceivers that introduce big jitter like ones for optical fiber, the old HUB that has direction 
control only may cause a transmission error because jitters on each HUB are added when several HUBs were 
connected in serial. The TMC2005 fixes that problem with jitter filtering and wave shaping through the following three 
steps. 
 
1) Input 

Sampling 

The TMC2005 samples a data on a network by eight times clock of the network data. 
 
2)  Jitter Filtering (DPLL) 
The TMC2005 filters the jitter (± 100nS at 2.5Mbps) of network data sampled by 8X clock through the internal digital 
PLL and stores the data into the buffer. 
 
3)  Wave Shaping Output 
The TMC2005 re-synchronizes and regenerates the network data at the same clock as the data rate.  
 
The capability of the jitter filtering is shown below. 
 

DATA RATE 

CAPABILITY OF JITTER FILTERING 

10Mbps ± 

25nS 

5Mbps ± 

50nS 

2.5Mbps ± 

100nS 

1.25Mbps ± 

200nS 

625Kbps ± 

400nS 

312.5Kbps ± 

800nS 

156.25Kbps ± 

1.6uS 

 

Maker
Microchip Technology Inc.
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