SMSC EMC1201/EMC1202
DATASHEET
Revision 1.0 (06-10-08)
Datasheet
PRODUCT FEATURES
EMC1201/EMC1202
General Description
The EMC1201 and EMC1202 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1201 has an
internal temperature sensor and the EMC1202 adds one
remote diode. Packaged in a SOT23-5, the EMC1201
provides an accurate, low-cost, low-current, solution for
critical temperature monitoring in applications such as
embedded systems or computers. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode extends battery
life in portable applications. The internal 11-bit sigma
delta temperature-to-digital converter provides superb
linearity, high accuracy and excellent noise immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 3uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±
3
º
C Accuracy 0
º
C to 85
º
C
SOT23-5 Lead-free RoHS Compliant Packages
Applications
Desktop and Notebook Computers
Thermostats
Smart batteries
Industrial/Automotive
Other Electronic Systems
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
EXTERNAL
TEMPERATURE
MONITOR
EMC1201
1
0
EMC1202
1
1
EMC1201/EMC1202
Temperature
Registers
BBUS
Interface
Local Temp
Diode
Switching
Current
Analog
Mux
DP
11-bit
delta-sigma
ADC
DN
BBUS
External
Diode for
EMC1202
Only
Single/Dual Single-Wire Temp
Sensor in SOT23-5 Using
SMSC BudgetBus
TM
Sensor
Interface
ORDER NUMBERS:
EMC1201-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1202-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
2
SMSC EMC1201/EMC1202
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 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.
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
3
Revision 1.0 (06-10-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1201 and EMC1202 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1201 and EMC1202 Pin Description
PIN
PIN NO.
DESCRIPTION
VDD
1
Supply Voltage V
DD
GND
2
Ground
BBUS
3
Serial Bus Interface to SMSC Host
GND/DP
4
Ground, or Diode 1 Positive Terminal, EMC1202 only
GND/DN
5
Ground, or Diode 1 Negative Terminal, EMC1202 only
5
4
1
2
3
VDD
GND
BBUS
GND/DN
GND/DP
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
4
SMSC EMC1201/EMC1202
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1201/EMC1202 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for SOT23-5
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
131.7
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
5
Revision 1.0 (06-10-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
545
560
μA
Active mode (continuous)
I
PD
1.8
2
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement (EMC1202 only)
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
± 1
± 3
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Active mode (continuous)
See
Section 3.3, "Power
Modes"
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
6
SMSC EMC1201/EMC1202
DATASHEET
Chapter 3 Product Description
The EMC1201 and EMC1202 are SOT23 temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1
shows a typical system overview:
Figure 3.1 System Overview
Thermal management consists of the host acquiring the temperature data from the EMC1201 or
EMC1202 and controlling the speed of one or more fans. Because the EMC1202 incorporates one
internal and one external temperature diode, up to two separate thermal zones can be monitored and
controlled. The host has the ability to compare measured temperature levels to preset limits and take
the appropriate action when values are found to be out of limit. The EMC1202 is compatible with CPU
substrate diodes.
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1202
Host
(KBC1100)
BBUS
Interface
DP
DN
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
7
Revision 1.0 (06-10-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1201 and EMC1202 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1202 Temperature Monitoring
The EMC1202, incorporates one internal diode and can monitor an additional temperature zone via
one external diode. An internal analog multiplexer switches between the internal and external diode.
Total conversion time for one internal and one external temperature reading is about 40ms. The
external diode can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1202 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1201 and EMC1202 communicate with a host controller, such as the KBC1100, through the
proprietary single wire SMSC BudgetBus™ Sensor Interface known as BBUS. The BBUS is a single
wire serial communication protocol between the computer host and its peripheral devices. Please refer
to the BBUS Specification for detailed information about the modes of operation.
fs
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
fs
1-bit
Sigma
Delta
Modulator
fs
Digital
Averaging
Filter
fs/2048
11-bit
Accurate
Conversion
V
DD
Internal or
Remote Diode
Bias
Diode
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
8
SMSC EMC1201/EMC1202
DATASHEET
3.3
Power Modes
The EMC1201 and EMC1202 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1201
and EMC1202 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
9
Revision 1.0 (06-10-08)
DATASHEET
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3, "Power Modes"
.
Si
ngle/
Dual
S
ingle
-Wire
T
e
mp
Sen
s
o
r i
n
S
O
T23-
5 Usin
g S
M
SC B
udge
tB
us
TM
S
ensor In
te
rfa
c
e
Dat
ashe
e
t
Revision 1.0 (0
6-10-
08)
10
SMSC EMC120
1/EMC1202
DA
T
ASHEET
Chapter 4 Package Outline
Figure 4.1 EMC1201/EMC1202 5 Pin SOT Package Outline; 1.6mm Body Width, 0.95mm Pitch
SEATING PLANE
ccc C
C
DETAIL "A" (SCALE: 2/1)
GAUGE PLANE
0
0.25
H
L
L1
SIDE VIEW
3-D VIEWS
INDEX AREA
(D/2 x E1/2)
3
3
5
2
4
4
1
2
3
N
4
6
N = 5 LEADS
N = 6 LEADS
NOTES:
1. "N" IS THE TOTAL NUMBER OF LEADS .
2. TRUE POSITION SPREAD TOLERANCE IS ± 0.10mm AT MAXIMUM MATERIAL CONDITION.
3. PACKAGE BODY DIMENSION "D" DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR
GATE BURRS. MAXIMUM MOLD FLASH, PROTRUSIONS OR GATE BURRS IS 0.25 mm PER
END. DIMENSION "E1" DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.
MAXIMUM INTERLEAD FLASH OR PROTRUSION IS 0.25 mm PER SIDE. "D1" & "E1"
DIMENSIONS ARE DETERMINED AT DATUM PLANE "H".
4. DIMENSIONS "b" & "c" APPLY TO THE FLAT SECTION OF THE LEAD BETWEEN 0.08 TO
0.15 mm FROM THE LEAD TIP.
5. DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
INDEX AREA INDICATED (SEE TOP VIEW).
6. FIVE LEAD PACKAGE IS A VERSION OF 6 LEAD PACKAGE, WHERE LEAD #5 HAS BEEN
REMOVED FROM 6 LEAD PACKAGE.
D
E
E1
e
5X b
SEE DETAIL "A"
c
TOP VIEW
END VIEW
A1
A2
A
A
INITIAL RELEASE
7/07/04
S.K.ILIEV
DECIMAL
X.X
X.XX
X.XXX
MATERIAL
FINISH
STD COMPLIANCE
THIRD ANGLE PROJECTION
PRINT W ITH "SCALE TO FIT"
DO NOT SCA LE DRAWING
APPROVED
ANGULAR
UNLESS OTHE RWISE SPECIFIED
DIMENSIONS ARE IN MILLIMETERS
AND TOLERANCES ARE:
DIM AND TOL PER ASME Y14.5M - 1994
DRAWN
CHECKED
NAME
SCALE
80 ARKAY DRIVE
HAUP PAUGE, NY 11788
USA
DWG NUMBER
TITLE
DATE
SHEET
REV
REVISION HISTORY
DES CRIP TION
REVISION
RELEASED BY
DATE
S.K.ILIEV
S.K.ILIEV
S.K.ILIEV
±1°
-
-
±0.025
±0.05
±0.1
7/07/04
1:1
7/06/04
7/06/04
A
JEDEC: MO-178 / AA, AB
1 OF 1
1.6mm BODY WIDTH, 0.95mm PITCH
PACKAGE OUTLINE: 5/6 PIN SOT
MO-5/6 SOT-2.9x1.6
SMSC EMC1201/EMC1202
DATASHEET
Revision 1.0 (06-10-08)
Datasheet
PRODUCT FEATURES
EMC1201/EMC1202
General Description
The EMC1201 and EMC1202 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1201 has an
internal temperature sensor and the EMC1202 adds one
remote diode. Packaged in a SOT23-5, the EMC1201
provides an accurate, low-cost, low-current, solution for
critical temperature monitoring in applications such as
embedded systems or computers. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode extends battery
life in portable applications. The internal 11-bit sigma
delta temperature-to-digital converter provides superb
linearity, high accuracy and excellent noise immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 3uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±
3
º
C Accuracy 0
º
C to 85
º
C
SOT23-5 Lead-free RoHS Compliant Packages
Applications
Desktop and Notebook Computers
Thermostats
Smart batteries
Industrial/Automotive
Other Electronic Systems
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
EXTERNAL
TEMPERATURE
MONITOR
EMC1201
1
0
EMC1202
1
1
EMC1201/EMC1202
Temperature
Registers
BBUS
Interface
Local Temp
Diode
Switching
Current
Analog
Mux
DP
11-bit
delta-sigma
ADC
DN
BBUS
External
Diode for
EMC1202
Only
Single/Dual Single-Wire Temp
Sensor in SOT23-5 Using
SMSC BudgetBus
TM
Sensor
Interface
ORDER NUMBERS:
EMC1201-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1202-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
2
SMSC EMC1201/EMC1202
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 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.
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
3
Revision 1.0 (06-10-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1201 and EMC1202 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1201 and EMC1202 Pin Description
PIN
PIN NO.
DESCRIPTION
VDD
1
Supply Voltage V
DD
GND
2
Ground
BBUS
3
Serial Bus Interface to SMSC Host
GND/DP
4
Ground, or Diode 1 Positive Terminal, EMC1202 only
GND/DN
5
Ground, or Diode 1 Negative Terminal, EMC1202 only
5
4
1
2
3
VDD
GND
BBUS
GND/DN
GND/DP
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
4
SMSC EMC1201/EMC1202
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1201/EMC1202 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for SOT23-5
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
131.7
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
5
Revision 1.0 (06-10-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
545
560
μA
Active mode (continuous)
I
PD
1.8
2
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement (EMC1202 only)
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
± 1
± 3
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Active mode (continuous)
See
Section 3.3, "Power
Modes"
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
6
SMSC EMC1201/EMC1202
DATASHEET
Chapter 3 Product Description
The EMC1201 and EMC1202 are SOT23 temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1
shows a typical system overview:
Figure 3.1 System Overview
Thermal management consists of the host acquiring the temperature data from the EMC1201 or
EMC1202 and controlling the speed of one or more fans. Because the EMC1202 incorporates one
internal and one external temperature diode, up to two separate thermal zones can be monitored and
controlled. The host has the ability to compare measured temperature levels to preset limits and take
the appropriate action when values are found to be out of limit. The EMC1202 is compatible with CPU
substrate diodes.
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1202
Host
(KBC1100)
BBUS
Interface
DP
DN
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
7
Revision 1.0 (06-10-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1201 and EMC1202 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1202 Temperature Monitoring
The EMC1202, incorporates one internal diode and can monitor an additional temperature zone via
one external diode. An internal analog multiplexer switches between the internal and external diode.
Total conversion time for one internal and one external temperature reading is about 40ms. The
external diode can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1202 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1201 and EMC1202 communicate with a host controller, such as the KBC1100, through the
proprietary single wire SMSC BudgetBus™ Sensor Interface known as BBUS. The BBUS is a single
wire serial communication protocol between the computer host and its peripheral devices. Please refer
to the BBUS Specification for detailed information about the modes of operation.
fs
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
fs
1-bit
Sigma
Delta
Modulator
fs
Digital
Averaging
Filter
fs/2048
11-bit
Accurate
Conversion
V
DD
Internal or
Remote Diode
Bias
Diode
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
8
SMSC EMC1201/EMC1202
DATASHEET
3.3
Power Modes
The EMC1201 and EMC1202 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1201
and EMC1202 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
9
Revision 1.0 (06-10-08)
DATASHEET
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3, "Power Modes"
.
Si
ngle/
Dual
S
ingle
-Wire
T
e
mp
Sen
s
o
r i
n
S
O
T23-
5 Usin
g S
M
SC B
udge
tB
us
TM
S
ensor In
te
rfa
c
e
Dat
ashe
e
t
Revision 1.0 (0
6-10-
08)
10
SMSC EMC120
1/EMC1202
DA
T
ASHEET
Chapter 4 Package Outline
Figure 4.1 EMC1201/EMC1202 5 Pin SOT Package Outline; 1.6mm Body Width, 0.95mm Pitch
SEATING PLANE
ccc C
C
DETAIL "A" (SCALE: 2/1)
GAUGE PLANE
0
0.25
H
L
L1
SIDE VIEW
3-D VIEWS
INDEX AREA
(D/2 x E1/2)
3
3
5
2
4
4
1
2
3
N
4
6
N = 5 LEADS
N = 6 LEADS
NOTES:
1. "N" IS THE TOTAL NUMBER OF LEADS .
2. TRUE POSITION SPREAD TOLERANCE IS ± 0.10mm AT MAXIMUM MATERIAL CONDITION.
3. PACKAGE BODY DIMENSION "D" DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR
GATE BURRS. MAXIMUM MOLD FLASH, PROTRUSIONS OR GATE BURRS IS 0.25 mm PER
END. DIMENSION "E1" DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.
MAXIMUM INTERLEAD FLASH OR PROTRUSION IS 0.25 mm PER SIDE. "D1" & "E1"
DIMENSIONS ARE DETERMINED AT DATUM PLANE "H".
4. DIMENSIONS "b" & "c" APPLY TO THE FLAT SECTION OF THE LEAD BETWEEN 0.08 TO
0.15 mm FROM THE LEAD TIP.
5. DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
INDEX AREA INDICATED (SEE TOP VIEW).
6. FIVE LEAD PACKAGE IS A VERSION OF 6 LEAD PACKAGE, WHERE LEAD #5 HAS BEEN
REMOVED FROM 6 LEAD PACKAGE.
D
E
E1
e
5X b
SEE DETAIL "A"
c
TOP VIEW
END VIEW
A1
A2
A
A
INITIAL RELEASE
7/07/04
S.K.ILIEV
DECIMAL
X.X
X.XX
X.XXX
MATERIAL
FINISH
STD COMPLIANCE
THIRD ANGLE PROJECTION
PRINT W ITH "SCALE TO FIT"
DO NOT SCA LE DRAWING
APPROVED
ANGULAR
UNLESS OTHE RWISE SPECIFIED
DIMENSIONS ARE IN MILLIMETERS
AND TOLERANCES ARE:
DIM AND TOL PER ASME Y14.5M - 1994
DRAWN
CHECKED
NAME
SCALE
80 ARKAY DRIVE
HAUP PAUGE, NY 11788
USA
DWG NUMBER
TITLE
DATE
SHEET
REV
REVISION HISTORY
DES CRIP TION
REVISION
RELEASED BY
DATE
S.K.ILIEV
S.K.ILIEV
S.K.ILIEV
±1°
-
-
±0.025
±0.05
±0.1
7/07/04
1:1
7/06/04
7/06/04
A
JEDEC: MO-178 / AA, AB
1 OF 1
1.6mm BODY WIDTH, 0.95mm PITCH
PACKAGE OUTLINE: 5/6 PIN SOT
MO-5/6 SOT-2.9x1.6
SMSC EMC1201/EMC1202
DATASHEET
Revision 1.0 (06-10-08)
Datasheet
PRODUCT FEATURES
EMC1201/EMC1202
General Description
The EMC1201 and EMC1202 are temperature sensors
that communicate with a host over a single-wire SMSC
BudgetBus™ Sensor Interface. The EMC1201 has an
internal temperature sensor and the EMC1202 adds one
remote diode. Packaged in a SOT23-5, the EMC1201
provides an accurate, low-cost, low-current, solution for
critical temperature monitoring in applications such as
embedded systems or computers. When used in
combination with an SMSC Super I/O host, such as a
keyboard controller, a complete thermal management
system is created. A power down mode extends battery
life in portable applications. The internal 11-bit sigma
delta temperature-to-digital converter provides superb
linearity, high accuracy and excellent noise immunity.
Features
Single-wire SMSC BudgetBus™ Sensor Interface
Low Power, 3.0V to 3.6V Supply
—
< 50uA at 1 conversion per second
—
< 3uA in Standby
External Temperature Sensor
—
Range -63.875
º
C to +191.875
º
C
—
0.125
º
C resolution
—
±
1
º
C Accuracy 60
º
C to 100
º
C
—
Diode Fault Reporting
Self Contained Internal Temperature Sensor
—
Range 0
º
C to +85
º
C
—
0.125
º
C resolution
—
±
3
º
C Accuracy 0
º
C to 85
º
C
SOT23-5 Lead-free RoHS Compliant Packages
Applications
Desktop and Notebook Computers
Thermostats
Smart batteries
Industrial/Automotive
Other Electronic Systems
Simplified Block Diagram
PART
NUMBER
INTERNAL
TEMPERATURE
MONITOR
EXTERNAL
TEMPERATURE
MONITOR
EMC1201
1
0
EMC1202
1
1
EMC1201/EMC1202
Temperature
Registers
BBUS
Interface
Local Temp
Diode
Switching
Current
Analog
Mux
DP
11-bit
delta-sigma
ADC
DN
BBUS
External
Diode for
EMC1202
Only
Single/Dual Single-Wire Temp
Sensor in SOT23-5 Using
SMSC BudgetBus
TM
Sensor
Interface
ORDER NUMBERS:
EMC1201-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
EMC1202-AGZQ-TR IN 5 PIN SOT23-5 LEAD-FREE ROHS COMPLIANT PACKAGE
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
2
SMSC EMC1201/EMC1202
DATASHEET
80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000, FAX (631) 273-3123
Copyright © 2008 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.
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
3
Revision 1.0 (06-10-08)
DATASHEET
Chapter 1 Pin Configuration
Figure 1.1 EMC1201 and EMC1202 Pin Configuration
1.1
Pin Description
Table 1.1 EMC1201 and EMC1202 Pin Description
PIN
PIN NO.
DESCRIPTION
VDD
1
Supply Voltage V
DD
GND
2
Ground
BBUS
3
Serial Bus Interface to SMSC Host
GND/DP
4
Ground, or Diode 1 Positive Terminal, EMC1202 only
GND/DN
5
Ground, or Diode 1 Negative Terminal, EMC1202 only
5
4
1
2
3
VDD
GND
BBUS
GND/DN
GND/DP
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
4
SMSC EMC1201/EMC1202
DATASHEET
1.2
Absolute Maximum Ratings
Note: Stresses above those listed could cause damage to the device. This is a stress rating only
and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied. When powering this device from
laboratory or system power supplies, it is important that the Absolute Maximum Ratings not be
exceeded or device failure can result. Some power supplies exhibit voltage spikes on their
outputs when the AC power is switched on or off. In addition, voltage transients on the AC
power line may appear on the DC output. If this possibility exists, it is suggested that a clamp
circuit be used.
Table 1.2 EMC1201/EMC1202 Maximum Ratings
DESCRIPTION
RATING
UNIT
Supply Voltage V
DD
-0.3 to 5.0
V
Voltage on any other pin
-0.3 to V
DD
+0.3
V
Operating Temperature Range
0 to 85
°C
Storage Temperature Range
-55 to 150
°C
Lead Temperature Range
Refer to JEDEC
Spec. J-STD-020
Package Thermal Characteristics for SOT23-5
Power Dissipation
TBD
Thermal Resistance(at 0 air flow)
131.7
°C/W
ESD Rating, All Pins Human Body Model
2000
V
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
5
Revision 1.0 (06-10-08)
DATASHEET
Chapter 2 Electrical Characteristics
Table 2.1 Electrical Characteristics
V
DD
=3.0V to 3.6V, T
A
= 0
°C to +85°C, Typical values at T
A
= 27
°C unless otherwise noted
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
CONDITIONS
DC Power
Supply Voltage
V
DD
3.0
3.3
3.6
V
Average Operating Current
I
DD
545
560
μA
Active mode (continuous)
I
PD
1.8
2
μA
Standby mode
Internal Temperature Measurement
Accuracy
±1
±3
°C
0
°C≤T
A
≤85°C
External Temperature Measurement (EMC1202 only)
Temperature Accuracy
Remote Diode 60
°C to 100°C
Remote Diode 0
°C to 125°C
± 1
± 3
°C
°C
15
°C≤T
A
≤70°C
0
°C≤T
A
≤85°C
ADC
Resolution
0.125
°C
Conversion Time per sensor
20
ms
Active mode (continuous)
See
Section 3.3, "Power
Modes"
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
6
SMSC EMC1201/EMC1202
DATASHEET
Chapter 3 Product Description
The EMC1201 and EMC1202 are SOT23 temperature sensors with a proprietary single wire SMSC
BudgetBus™ Sensor Interface. Temperature information is communicated to a host device via the
serial bus. All intelligence regarding the interpretation of temperature resides in the host.
Figure 3.1
shows a typical system overview:
Figure 3.1 System Overview
Thermal management consists of the host acquiring the temperature data from the EMC1201 or
EMC1202 and controlling the speed of one or more fans. Because the EMC1202 incorporates one
internal and one external temperature diode, up to two separate thermal zones can be monitored and
controlled. The host has the ability to compare measured temperature levels to preset limits and take
the appropriate action when values are found to be out of limit. The EMC1202 is compatible with CPU
substrate diodes.
3.1
Temperature Monitors
Thermal diode temperature measurements are based on the change in forward bias voltage (
ΔV
BE
) of
a diode when operated at two different currents:
The change in
Δ
V
BE
voltage is proportional to absolute temperature T.
where:
k = Boltzmann’s constant
T = absolute temperature in Kelvin
q = electron charge
η
= diode ideality factor
EMC1202
Host
(KBC1100)
BBUS
Interface
DP
DN
BBUS
⎟⎟
⎠
⎞
⎜⎜
⎝
⎛
=
−
=
Δ
LOW
HIGH
LOW
BE
HIGH
BE
BE
I
I
q
kT
V
V
V
ln
_
_
η
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
7
Revision 1.0 (06-10-08)
DATASHEET
Figure 3.2 Detailed Block Diagram of Temperature Monitor Architecture
Figure 3.2
shows a detailed block diagram of the temperature measurement circuit. As shown, the
EMC1201 and EMC1202 incorporates switched capacitor technology that samples the temperature
diode voltage at two bias currents and holds the difference voltage. The sample frequency is 100kHz
and the current levels Ihigh and Ilow are 170uA and 10uA respectively.
The output of the switched capacitor sample and hold circuit interfaces to a single bit delta sigma
analog to digital converter. This ADC runs at 100kHz sample frequency and its output is digitally filtered
and averaged over 2048 samples effectively generating 11 bit accuracy.
The advantages of this architecture over Nyquist rate FLASH or SAR converters are superb linearity
and inherent noise immunity. The linearity can be directly attributed to the delta sigma ADC single bit
comparator while the noise immunity is achieved by the digital averaging filter. The overall effective
bandwidth of the system is fs/2048 which translates to a 50Hz bandwidth at 100kHz sample rate.
Conversion time equals about 20ms per temperature monitor.
3.1.1
EMC1202 Temperature Monitoring
The EMC1202, incorporates one internal diode and can monitor an additional temperature zone via
one external diode. An internal analog multiplexer switches between the internal and external diode.
Total conversion time for one internal and one external temperature reading is about 40ms. The
external diode can be either a CPU substrate diode or a discrete diode connected transistor like the
2N3904 or 2N3906. External diode connected transistors examples are shown in
Figure 3.3
:
Figure 3.3 EMC1202 External Diode Examples
3.2
SMSC BudgetBus™ Sensor Interface
The EMC1201 and EMC1202 communicate with a host controller, such as the KBC1100, through the
proprietary single wire SMSC BudgetBus™ Sensor Interface known as BBUS. The BBUS is a single
wire serial communication protocol between the computer host and its peripheral devices. Please refer
to the BBUS Specification for detailed information about the modes of operation.
fs
Delta Vbe
Sample
&
Hold
I
bias
I
low
I
high
fs
1-bit
Sigma
Delta
Modulator
fs
Digital
Averaging
Filter
fs/2048
11-bit
Accurate
Conversion
V
DD
Internal or
Remote Diode
Bias
Diode
Local Ground
to
DP
Typical remote
substrate transistor
i.e. CPU substrate PNP
Typical remote
discrete PNP transistor
i.e. 2N3906
Typical remote
discrete NPN transistor
i.e. 2N3904
to
DN
to
DP
to
DN
to
DP
to
DN
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
Revision 1.0 (06-10-08)
8
SMSC EMC1201/EMC1202
DATASHEET
3.3
Power Modes
The EMC1201 and EMC1202 have two basic modes of operation:
Standby Mode:
The host can initiate standby mode by actively pulling the BBUS low. When the Host places the device
in standby mode, the device immediately powers down to draw < 2uA of supply current. It will remain
in this state until it is awakened by the host. If the host pulls the BBUS line low while temperature data
is being clocked out, the device will not enter standby mode until completion of the data transfer. After
entering standby mode, the device will remain in this mode until it is forced into active mode by the
host. The transition from standby to active mode occurs when the host is no longer pulling the BBUS
low.
Active Mode:
The host initiates active mode by enabling a weak pull up on the BBUS. In this mode, the EMC1201
and EMC1202 continuously convert temperature data. During the time that the device is actively
converting a temperature, the BBUS is in tri-state mode, and the Host places a weak pull-up on the
bus to prevent it from floating. After a conversion is completed, the device automatically clocks out the
data from the most recent conversion to the host. When the data packet has been entirely clocked out,
the BBUS returns to tri-state mode, and the ADC begins converting the next temperature sample.
While BBUS is in tri-state mode, the host can command the device to standby mode.
3.4
Temperature Data Format
Temperature readings are coded in 2’s complement format with a -64ºC offset. This format spans from
–63.875ºC to +191.875ºC with 0.125ºC resolution. A temperature measurement outside this range is
reported as either –63.875ºC or +191.875ºC. The host must add 64ºC to calculate the actual
temperature.
Table 3.1
shows example temperature readings and the value that will be reported on the
BBUS.
As shown in
Table 3.1
, 400h is reserved for diode fault signaling which occurs when open or short
conditions are detected between the external DP and DN pins.
Table 3.1 Temperature Data Format
ACTUAL TEMP.
(ºC)
2’S COMPLEMENT
OF -64ºC OFFSET
HEX
Diode Fault
100 0000 0000
400
-63.875
100 0000 0001
401
-63.000
100 0000 1000
408
-1.000
101 1111 1000
5F8
0.000
110 0000 0000
600
+0.125
110 0000 0001
601
+1.000
110 0000 1000
608
Single/Dual Single-Wire Temp Sensor in SOT23-5 Using SMSC BudgetBus
TM
Sensor Interface
Datasheet
SMSC EMC1201/EMC1202
9
Revision 1.0 (06-10-08)
DATASHEET
3.5
Conversion Rate
The conversion rate can be controlled by the host. This is accomplished by periodically placing the
device in standby as described in
Section 3.3, "Power Modes"
.
Si
ngle/
Dual
S
ingle
-Wire
T
e
mp
Sen
s
o
r i
n
S
O
T23-
5 Usin
g S
M
SC B
udge
tB
us
TM
S
ensor In
te
rfa
c
e
Dat
ashe
e
t
Revision 1.0 (0
6-10-
08)
10
SMSC EMC120
1/EMC1202
DA
T
ASHEET
Chapter 4 Package Outline
Figure 4.1 EMC1201/EMC1202 5 Pin SOT Package Outline; 1.6mm Body Width, 0.95mm Pitch
SEATING PLANE
ccc C
C
DETAIL "A" (SCALE: 2/1)
GAUGE PLANE
0
0.25
H
L
L1
SIDE VIEW
3-D VIEWS
INDEX AREA
(D/2 x E1/2)
3
3
5
2
4
4
1
2
3
N
4
6
N = 5 LEADS
N = 6 LEADS
NOTES:
1. "N" IS THE TOTAL NUMBER OF LEADS .
2. TRUE POSITION SPREAD TOLERANCE IS ± 0.10mm AT MAXIMUM MATERIAL CONDITION.
3. PACKAGE BODY DIMENSION "D" DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR
GATE BURRS. MAXIMUM MOLD FLASH, PROTRUSIONS OR GATE BURRS IS 0.25 mm PER
END. DIMENSION "E1" DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSION.
MAXIMUM INTERLEAD FLASH OR PROTRUSION IS 0.25 mm PER SIDE. "D1" & "E1"
DIMENSIONS ARE DETERMINED AT DATUM PLANE "H".
4. DIMENSIONS "b" & "c" APPLY TO THE FLAT SECTION OF THE LEAD BETWEEN 0.08 TO
0.15 mm FROM THE LEAD TIP.
5. DETAILS OF PIN 1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE
INDEX AREA INDICATED (SEE TOP VIEW).
6. FIVE LEAD PACKAGE IS A VERSION OF 6 LEAD PACKAGE, WHERE LEAD #5 HAS BEEN
REMOVED FROM 6 LEAD PACKAGE.
D
E
E1
e
5X b
SEE DETAIL "A"
c
TOP VIEW
END VIEW
A1
A2
A
A
INITIAL RELEASE
7/07/04
S.K.ILIEV
DECIMAL
X.X
X.XX
X.XXX
MATERIAL
FINISH
STD COMPLIANCE
THIRD ANGLE PROJECTION
PRINT W ITH "SCALE TO FIT"
DO NOT SCA LE DRAWING
APPROVED
ANGULAR
UNLESS OTHE RWISE SPECIFIED
DIMENSIONS ARE IN MILLIMETERS
AND TOLERANCES ARE:
DIM AND TOL PER ASME Y14.5M - 1994
DRAWN
CHECKED
NAME
SCALE
80 ARKAY DRIVE
HAUP PAUGE, NY 11788
USA
DWG NUMBER
TITLE
DATE
SHEET
REV
REVISION HISTORY
DES CRIP TION
REVISION
RELEASED BY
DATE
S.K.ILIEV
S.K.ILIEV
S.K.ILIEV
±1°
-
-
±0.025
±0.05
±0.1
7/07/04
1:1
7/06/04
7/06/04
A
JEDEC: MO-178 / AA, AB
1 OF 1
1.6mm BODY WIDTH, 0.95mm PITCH
PACKAGE OUTLINE: 5/6 PIN SOT
MO-5/6 SOT-2.9x1.6