DS26LS31C/DS26LS31M Quad High Speed Differential Line Driver
June 1998
DS26LS31C/DS26LS31M
Quad High Speed Differential Line Driver
General Description
The DS26LS31 is a quad differential line driver designed for
digital data transmission over balanced lines. The
DS26LS31 meets all the requirements of EIA Standard
RS-422 and Federal Standard 1020. It is designed to provide
unipolar differential drive to twisted-pair or parallel-wire
transmission lines.
The circuit provides an enable and disable function common
to all four drivers. The DS26LS31 features TRI-STATE
®
out-
puts and logically ANDed complementary outputs. The in-
puts are all LS compatible and are all one unit load.
Features
n
n
n
n
n
n
n
n
n
n
Output skew — 2.0 ns typical
Input to output delay — 10 ns typical
Operation from single 5V supply
Outputs won’t load line when V
CC
= 0V
Four line drivers in one package for maximum package
density
Output short-circuit protection
Complementary outputs
Meets the requirements of EIA Standard RS-422
Pin compatible with AM26LS31
Available in military and commercial temperature range
Logic and Connection Diagrams
DS005778-1
Dual-In-Line Package
DS005778-2
Top View
Order Number DS26LS31CM, or DS26LS31CN
See NS Package M16A or N16E
For Complete Military Product Specifications,
refer to the appropriate SMD or MDS.
Order Number DS26LS31MJ/883, DS26LS31ME/883 or DS26LS31MW/883
See NS Package E20A, J16A or W16A
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
© 2000 National Semiconductor Corporation
DS005778
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DS26LS31C/DS26LS31M
Absolute Maximum Ratings
(Note 2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage
Input Voltage
Output Voltage
Output Voltage (Power OFF)
Maximum Power Dissipation (Note 1) at 25˚C
Cavity Package
Molded DIP Package
SO Package
7V
7V
5.5V
−0.25 to 6V
1509 mW
1476 mW
1051 mW
Operating Conditions
Min
Supply Voltage, V
CC
DS26LS31M
DS26LS31
Temperature, T
A
DS26LS31M
DS26LS31
4.5
4.75
−55
0
Max
5.5
5.25
+125
+70
Units
V
V
˚C
˚C
Note 1:
Derate cavity package 10.1 mW/˚C above 25˚C; derate molded DIP
package 11.9 mW/˚C above 25˚C; derate SO package 8.41 mW/˚C above
25˚C.
Electrical Characteristics
(Notes 3, 4, 5)
Symbol
V
OH
V
OL
V
IH
V
IL
I
IL
I
IH
I
I
I
O
V
CL
I
SC
I
CC
Parameter
Output High Voltage
Output Low Voltage
Input High Voltage
Input Low Voltage
Input Low Current
Input High Current
Input Reverse Current
TRI-STATE Output Current
Input Clamp Voltage
Output Short-Circuit Current
Power Supply Current
All Outputs Disabled
or Active
V
IN
= 0.4V
V
IN
= 2.7V
V
IN
= 7V
V
O
= 2.5V
V
O
= 0.5V
I
IN
= −18 mA
−30
35
−40
Conditions
I
OH
= −20 mA
I
OL
= 20 mA
2.0
0.8
−200
20
0.1
20
−20
−1.5
−150
60
Min
2.5
0.5
Typ
Max
Units
V
V
V
V
µA
µA
mA
µA
µA
V
mA
mA
Switching Characteristics
V
CC
= 5V, T
A
= 25˚C
Symbol
t
PLH
t
PHL
Skew
t
LZ
t
HZ
t
ZL
t
ZH
Parameter
Input to Output
Input to Output
Output to Output
Enable to Output
Enable to Output
Enable to Output
Enable to Output
Conditions
C
L
= 30 pF
C
L
= 30 pF
C
L
= 30 pF
C
L
= 10 pF, S2 Open
C
L
= 10 pF, S1 Open
C
L
= 30 pF, S2 Open
C
L
= 30 pF, S1 Open
Min
Typ
10
10
2.0
15
15
20
20
Max
15
15
6.0
35
25
30
30
Units
ns
ns
ns
ns
ns
ns
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 −55˚C to +125˚C temperature range for the DS726LS31M and across the 0˚C to +70˚C range
for the DS26LS31. All typicals are given for V
CC
= 5V and T
A
= 25˚C.
Note 4:
All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to ground unless otherwise specified.
Note 5:
Only one output at a time should be shorted.
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2
DS26LS31C/DS26LS31M
AC Test Circuit and Switching Time Waveforms
DS005778-3
S1 and S2 of load circuit are closed except where shown.
FIGURE 1. AC Test Circuit
DS005778-4
f = 1 MHz, t
r
≤
15 ns, t
f
≤
6 ns
FIGURE 2. Propagation Delays
DS005778-5
f = 1 MHz, t
r
≤
15 ns, t
f
≤
6 ns
FIGURE 3. Enable and Disable Times
Typical Applications
Two-Wire Balanced System, RS-422
DS005778-6
Note 6:
R
T
is optional although highly recommended to reduce reflection.
3
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