DS96177
RS-485/RS-422 Differential Bus Repeater
General Description
The DS96177 Differential Bus Repeater is a monolithic inte-
grated device designed for one-way data communication on
multipoint bus transmission lines. This device is designed for
balanced transmission bus line applications and meets EIA
Standard RS-485 and RS-422A. The device is designed to
improve the performance of the data communication over
long bus lines. The DS96177 has an active high Enable.
The DS96177 features positive and negative current limiting
and TRI-STATE
®
outputs for the receiver and driver. The re-
ceiver features high input impedance, input hysteresis for in-
creased noise immunity, and input sensitivity of 200 mV over
a common mode input voltage range of −12V to +12V. The
driver features thermal shutdown for protection from line
fault conditions. Thermal shutdown is designed to occur at a
junction temperature of approximately 160˚C. The driver is
designed to drive current loads up to 60 mA maximum.
The DS96177 is designed for optimum performance when
used on transmission buses employing the DS96172 and
DS96174 differential line drivers, DS96173 and DS96175
differential line receivers, or DS96176 differential bus trans-
ceivers.
Features
n
Meets EIA Standard RS-422A and RS-485
n
Designed for multipoint transmission on long bus lines in
noisy environments
n
TRI-STATE outputs
n
Bus voltage range −7.0V to +12V
n
Positive and negative current limiting
n
Driver output capability
±
60 mA max
n
Driver thermal shutdown protection
n
Receiver input high impedance
n
Receiver input sensitivity of
±
200 mV
n
Receiver input hysteresis of 50 mV typical
n
Operates from single 5.0V supply
n
Low power requirements
Connection Diagram
Function Table
Differential Inputs
Enable
Outputs
A–B
E
T
Y
Z
V
ID
≥
0.2V
H
H
H
L
V
ID
≤
−0.2V
H
L
L
H
X
L
Z
Z
Z
Note: T is an output pin only, monitoring the BUS (RO).
H = High Level
L = Low Level
X = Immaterial
Z = High Impedance (off)
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
8-Lead Dual-In-Line Package
DS009644-1
Top View
Order Number DS96177CN
See NS Package Number N08E
October 1993
DS96177
RS-485/RS-422
Differential
Bus
Repeater
© 1999 National Semiconductor Corporation
DS009644
www.national.com
Absolute Maximum Ratings
(Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Storage Temperature Range
Ceramic DIP
−65˚C to +175˚C
Molded DIP
−65˚C to +150˚C
Lead Temperature
Ceramic DIP (Soldering, 60 sec.)
300˚C
Molded DIP (Soldering, 10 sec.)
265˚C
Maximum Power Dissipation (Note 1) at 25˚C
Molded Package
930 mW
Supply Voltage
7.0V
Input Voltage
5.5V
Recommended Operating
Conditions
Min Typ
Max
Units
Supply Voltage (V
CC
)
4.75
5.0
5.25
V
Voltage at any Bus Terminal
(Separately or Common
−7.0
12
V
Mode) (V
I
or V
CM
)
Differential Input Voltage
(V
ID
)
±
12
V
Output Current HIGH (I
OH
)
Driver
−60
mA
Receiver
−400
µA
Output Current LOW (I
OL
)
Driver
60
mA
Receiver
16
Operating Temperature (T
A
)
0
25
70
˚C
Note 1: Derate molded DIP package 7.5 mW/˚C above 25˚C.
Electrical Characteristics
(Notes 3, 4)
Over recommended temperature, common mode input voltage, and supply voltage ranges, unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
DRIVER SECTION
V
IH
Input Voltage HIGH
2.0
V
V
IL
Input Voltage LOW
0.8
V
V
IC
Input Clamp Voltage
I
I
= −18 mA
−1.5
V
|V
OD1
|
Differential Output Voltage
I
O
= 0 mA
6.0
V
|V
OD2
|
Differential Output Voltage
R
L
= 100
Ω
,
Figure 1
2.0
2.25
V
R
L
= 54
Ω
,
Figure 1
and
Figure 2
1.5
2.0
∆
|V
OD2
|
Change in Magnitude of Differential
R
L
= 100
Ω
,
Figure 1
±
0.2
V
Output Voltage (Note 5)
R
L
= 54
Ω
Figure 1
and
Figure 2
V
CM
= 0V
V
OC
Common Mode Output Voltage (Note 6)
R
L
= 54
Ω
or 100
Ω
3.0
V
∆
|V
OC
|
Change in Magnitude of Common Mode
Figure 1
±
0.2
V
Output Voltage (Note 5)
I
O
Output Current with Power Off
V
CC
= 0V, V
O
= −7.0V to +12V
±
100
µA
I
OZ
High Impedance State Output Current
V
O
= −7.0V to +12V
±
50
±
200
µA
I
IH
Input Current HIGH
V
I
= 2.7V
20
µA
I
IL
Input Current LOW
V
I
= 0.5V
−100
µA
I
OS
Short Circuit Output Current
V
O
= −7.0V
−250
(Note 10)
V
O
= 0V
−150
mA
V
O
= V
CC
150
V
O
= 12V
250
I
CC
Supply Current
No Load
Outputs Enabled
35
mA
Outputs Disabled
40
RECEIVER SECTION
V
TH
Differential Input
V
O
= 2.7V, I
O
= −0.4 mA
0.2
V
High Threshold Voltage
V
TL
Differential Input Low
V
O
= 0.5V, I
O
= 8.0 mA
−0.2
V
Threshold Voltage (Note 7)
V
T+
−V
T−
Hysteresis (Note 8)
V
CM
= 0V
50
mV
V
IH
Enable Input Voltage HIGH
2.0
V
V
IL
Enable Input Voltage LOW
0.8
V
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2
Electrical Characteristics
(Notes 3, 4) (Continued)
Over recommended temperature, common mode input voltage, and supply voltage ranges, unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
RECEIVER SECTION
V
IC
Enable Input Clamp Voltage
I
I
= −18 mA
−1.5
V
V
OH
High Level Output Voltage
V
ID
= 200 mV, I
OH
= −400 µA,
Figure 3
2.7
V
V
OL
Low Level Output Voltage
V
ID
= −200 mV,
I
OL
= 8.0 mA
0.45
V
Figure 3
I
OL
= 16 mA
0.50
I
OZ
High-Impedance State Output
V
O
= 0.4V
−360
µA
V
O
= 2.4V
20
I
I
Line Input Current (Note 9)
Other Input = 0V
V
I
= 12V
1.0
mA
V
I
= −7.0V
−0.8
I
IH
Enable Input Current HIGH
V
IH
= 2.7V
20
µA
I
IL
Enable Input Current LOW
V
IL
= 0.4V
−100
µA
R
I
Input Resistance
12
k
Ω
I
OS
Short Circuit Output Current
(Note 10)
−15
−85
mA
I
CC
Supply Current (Total Package)
No Load
Outputs Enabled
35
mA
Outputs Disabled
40
Drive Switching Characteristics
V
CC
= 5.0V, T
A
= 25˚C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t
DD
Differential Output Delay Time
R
L
= 60
Ω
,
Figure 4
15
25
ns
t
TD
Differential Output Transition Time
R
L
= 60
Ω
,
Figure 4
15
25
ns
t
PLH
Propagation Delay Time,
R
L
= 27
Ω
,
Figure 5
12
20
ns
Low-to-High Level Output
t
PHL
Propagation Delay Time,
R
L
= 27
Ω
,
Figure 5
12
20
ns
High-to-Low Level Output
t
PZH
Output Enable Time to High Level
R
L
= 110
Ω
,
Figure 6
25
45
ns
t
PZL
Output Enable Time to Low Level
R
L
= 110
Ω
,
Figure 7
25
40
ns
t
PHZ
Output Disable Time from High Level
R
L
= 110
Ω
,
Figure 6
20
25
ns
t
PLZ
Output Disable Time from Low Level
R
L
= 110
Ω
,
Figure 7
29
35
ns
Receiver Switching Characteristics
V
CC
= 5.0V, T
A
= 25˚C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t
PLH
Propagation Delay Time,
V
ID
= 0V to 3.0V,
16
25
ns
Low-to-High Level Output
C
L
= 15 pF,
Figure 8
t
PHL
Propagation Delay Time,
16
25
ns
High-to-Low Level Output
t
PZH
Output Enable Time to High Level
C
L
= 15 pF,
Figure 9
15
22
ns
t
PZL
Output Enable Time to Low Level
15
22
ns
t
PHZ
Output Disable Time from High Level
C
L
= 5.0 pF,
Figure 9
14
30
ns
t
PLZ
Output Disable Time from Low Level
24
40
ns
Note 2: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the devices
should be operated at these limits. The tables of “Electrical Characteristics” provide conditions for actual device operation.
Note 3: Unless otherwise specified Min/Max limits apply across the 0˚C to +70˚C range for the DS96177. All typicals are given for V
CC
= 5V and T
A
= 25˚C.
Note 4: All currents into the device pins are positive; all currents out of the device pins are negative. All voltages are referenced to ground unless otherwise specified.
Note 5:
∆
|V
OD
| and
∆
|V
OC
| are the changes in magnitude of V
OD
, V
OC
respectively, that occur when the input is changed from a high level to a low level.
Note 6: In EIA Standards RS-422A and RS-485, V
OC
, which is the average of the two output voltages with respect to ground, is called output offset voltage, V
OS
.
Note 7: The algebraic convention, when the less positive (more negative) limit is designated minimum, is used in this data sheet for common mode input voltage
and threshold voltage levels only.
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3
Receiver Switching Characteristics
(Continued)
Note 8: Hysteresis is the difference between the positive-going input threshold voltage, V
T+
, and the negative going input threshold voltage, V
T−
.
Note 9: Refer to EIA Standards RS-485 for exact conditions.
Note 10: Only one output at a time should be shorted.
Parameter Measurement Information
DS009644-2
FIGURE 1. Driver V
OD2
and V
OC
DS009644-4
FIGURE 2. Driver V
OD2
with Varying
Common Mode Voltage
DS009644-3
FIGURE 3. Receiver V
OH
and V
OL
DS009644-5
DS009644-6
FIGURE 4. Driver Differential Output Delay and Transition Times
DS009644-7
DS009644-8
FIGURE 5. Drive Propagation Times
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4
Parameter Measurement Information
(Continued)
DS009644-9
DS009644-10
FIGURE 6. Driver Enable and Disable Times (t
PZH
, t
PHZ
)
DS009644-11
DS009644-12
FIGURE 7. Driver Enable and Disable Times (t
PZL
, t
PLZ
)
DS009644-13
DS009644-14
FIGURE 8. Receiver Propagation Delay Times
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5
Parameter Measurement Information
(Continued)
Note 11: The input pulse is supplied by a generator having the following characteristics: PRR = 1.0 MHz, duty cycle
≈
50%, t
r
≤
6.0 ns, t
f
≤
6.0 ns, Z
O
= 50
Ω
.
Note 12: C
L
includes probe and stray capacitance.
Note 13: DS96177 Enable is active high.
Note 14: All diodes are 1N916 or equivalent.
DS009644-15
DS009644-16
DS009644-17
DS009644-18
DS009644-19
FIGURE 9. Receiver Enable and Disable Times
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6
Typical Application
DS009644-20
The line length should be terminated at both ends in its characteristic impedance.
Stub lengths off the main line should be kept as short as possible.
Repeater control logic not shown
FIGURE 10.
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7
Physical Dimensions
inches (millimeters) unless otherwise noted
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tems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, and whose fail-
ure to perform when properly used in accordance
with instructions for use provided in the labeling, can
be reasonably expected to result in a significant injury
to the user.
2. A critical component is any component of a life support
device or system whose failure to perform can be rea-
sonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.
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Molded Dual-In-Line Package (N)
Order Number DS96177CN
NS Package Number N08E
DS96177
RS-485/RS-422
Differential
Bus
Repeater
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.