DS96172/DS96174
RS-485/RS-422 Quad Differential Line Drivers
General Description
The DS96172 and DS96174 are high speed quad differential
line drivers designed to meet EIA Standard RS-485. The de-
vices have TRI-STATE
outputs and are optimized for bal-
anced multipoint data bus transmission at rates up to
10 Mbps. The drivers have wide positive and negative com-
mon mode range for multipoint applications in noisy environ-
ments. Positive and negative current-limiting is provided
which protects the drivers from line fault conditions over a
+12V to -7.0V common mode range. A thermal shutdown
feature is also provided and occurs at junction temperature
of approximately 160C. The DS96172 features an active
high and active low Enable, common to all four drivers. The
DS96174 features separate active high Enables for each
driver pair. Compatible RS-485 receivers, transceivers, and
repeaters are also offered to provide optimum bus perfor-
mance.
The
respective
device
types
are
DS96173,
DS96175, DS96176 AND DS96177.
Features
n
Meets EIA Standard RS-485 and RS-422A
n
Monotonic differential output switching
n
Transmission rate to 10 Mbs
n
TRI-STATE outputs
n
Designed for multipoint bus transmission
n
Common mode output voltage range: -7V to +12V
n
Operates from single +5V supply
n
Thermal shutdown protection
n
DS96172/DS96174 are lead and function compatible
with the SN75172/75174 or the AM26LS31/MC3487
respectively
Connection Diagrams
TRI-STATE
is a registered trademark of National Semiconductor Corporation.
16-Lead DIP
DS96172
DS009626-1
Top View
16-Lead DIP
DS96174
DS009626-2
Top View
Order Number DS96172CN or DS96174CN
See NS Package Number N16E
June 1998
DS96172/DS96174
RS-485/RS-422
Quad
Differential
Line
Drivers
1998 National Semiconductor Corporation
DS009626
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
Molded DIP
-65C to +150C
Operating Temperature Range
0C to +70C
Lead Temperature
Molded DIP (soldering, 10
sec.)
265C
Supply Voltage
7V
Enable Input Voltage
5.5V
Maximum Power Dissipation
(Note 1)
25C
N-Molded Package
1.98W
Recommended Operating
Conditions
Min
Typ
Max
Units
Supply Voltage (V
CC
)
4.75
5
5.25
V
Common Mode Output
Voltage (V
OC
)
-7
+12
V
Output Current HIGH (I
OH
)
-60
mA
Output Current LOW (I
OL
)
60
mA
Operating Temperature (T
A
)
0
25
70
C
Note 1: Derate molded DIP package 16mW/C above 25C.
Electrical Characteristics
(Notes 3, 4)
over recommended temperature and supply voltage ranges, unless otherwise specified
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
IH
Input Voltage HIGH
2
V
V
IL
Input Voltage LOW
0.8
V
V
OH
Output Voltage HIGH
I
OH
= -20 mA
3.1
V
V
OL
Output Voltage LOW
I
OL
= 20 mA
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
V
|V
OD2
|
Differential Output Voltage
R
L
= 54
,
Figure 1
1.5
2
V
R
L
= 100
,
Figure 1
2
2.3
V
|V
OD
|
Change in Magnitude of Differential
R
L
= 54
or 100
,
Figure 1
0.2
V
Output Voltage (Note 5)
V
OC
Common Mode Output Voltage (Note 6)
R
L
= 54
,
Figure 1
3
V
|V
OC
|
Change in Magnitude of Common Mode
0.2
V
Output Voltage (Note 5)
I
O
Output Current with Power Off
V
CC
= 0V, V
O
= -7.0V to 12V
100
A
I
OZ
High Impedance State Output Current
V
O
= -7.0V to 12V
50
200
A
I
IH
Input Current HIGH
V
I
= 2.7V
20
A
I
IL
Input Current LOW
V
I
= 0.5V
-100
A
I
OS
Short Circuit Output Current
V
O
= -7.0V
-250
(Note 7)
V
O
= 0V
-150
mA
V
O
= V
CC
150
V
O
= 12V
250
I
CC
Supply Current (All Drivers)
No Load
Outputs Enabled
50
70
mA
Output Disabled
50
60
Switching Characteristics
V
CC
= 5V, T
A
= 25C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t
DD
Differential Output Delay Time
R
L
= 60
,
Figure 2
15
25
ns
t
TD
Differential Output Transition Time
15
25
ns
t
PLH
Propagation Delay Time,
R
L
= 27
,
Figure 3
12
20
ns
Low-to-High Level Output
t
PHL
Propagation Delay Time,
12
20
ns
High-to-Low Level Output
t
PZH
Output Enable Time to High Level
R
L
= 110
,
Figure 4
30
45
ns
t
PZL
Output Enable Time to Low Level
R
L
= 110
,
Figure 5
30
45
ns
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2
Switching Characteristics
(Continued)
V
CC
= 5V, T
A
= 25C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
t
PHZ
Output Disable Time from High Level
R
L
= 110
,
Figure 4
25
35
ns
t
PLZ
Output Disable Time from Low Level
R
L
= 110
,
Figure 5
30
45
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 0C to +70C range for the DS96172/DS96174. All typicals are given for V
CC
= 5V and T
A
= 25C.
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
and 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: Only one output at a time should be shorted.
Parameter Measurement Information
DS009626-4
FIGURE 1. Differential and Common Mode Output Voltage
DS009626-5
DS009626-6
FIGURE 2. Differential Output Delay and Transition Times
DS009626-7
DS009626-8
FIGURE 3. Propagation Delay Times
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3
Parameter Measurement Information
(Continued)
Note 8: The input pulse is supplied by a generator having the following characteristics: PRR = 1.0 MHz, duty cycle = 50%, t
r
5.0 ns, t
f
5.0 ns, Z
O
= 50
.
Note 9: C
L
includes probe and jig capacitance.
Note 10: DS96172 with active high and active low Enables is shown here. DS96174 has active high Enable only.
Note 11: To test the active low Enable E of DS96172, ground E and apply an inverted waveform to E . DS96174 has active high Enable only.
Function Tables
DS96172
Input
Enables
Outputs
A
E
E
Y
Z
H
H
X
H
L
L
H
X
L
H
H
X
L
H
L
L
X
L
L
H
X
L
H
Z
Z
DS96174
Input
Enable
Outputs
Y
Z
H
H
H
L
L
H
L
H
X
L
Z
Z
H = High Level
X = Immaterial
L = Low Level
Z = High Impedance (off)
DS009626-9
DS009626-10
FIGURE 4. t
PZH
and t
PHZ
DS009626-11
DS009626-12
FIGURE 5. t
PZL
and t
PLZ
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4
Typical Application
DS009626-13
Note: 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.
FIGURE 6.
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5
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