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
nOutput skew—2.0 ns typical
nInput to output delay—10 ns typical
nOperation from single 5V supply
nOutputs won’t load line when V
CC
=0V
nFour line drivers in one package for maximum package
density
nOutput short-circuit protection
nComplementary outputs
nMeets the requirements of EIA Standard RS-422
nPin compatible with AM26LS31
nAvailable in military and commercial temperature range
Logic and Connection Diagrams
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
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
June 1998
DS26LS31C/DS26LS31M Quad High Speed Differential Line Driver
© 2000 National Semiconductor Corporation DS005778 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.
Supply Voltage 7V
Input Voltage 7V
Output Voltage 5.5V
Output Voltage (Power OFF) −0.25 to 6V
Maximum Power Dissipation (Note 1) at 25˚C
Cavity Package 1509 mW
Molded DIP Package 1476 mW
SO Package 1051 mW
Operating Conditions
Min Max Units
Supply Voltage, V
CC
DS26LS31M 4.5 5.5 V
DS26LS31 4.75 5.25 V
Temperature, T
A
DS26LS31M −55 +125 ˚C
DS26LS31 0 +70 ˚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 Parameter Conditions Min Typ Max Units
V
OH
Output High Voltage I
OH
= −20 mA 2.5 V
V
OL
Output Low Voltage I
OL
= 20 mA 0.5 V
V
IH
Input High Voltage 2.0 V
V
IL
Input Low Voltage 0.8 V
I
IL
Input Low Current V
IN
= 0.4V −40 −200 µA
I
IH
Input High Current V
IN
= 2.7V 20 µA
I
I
Input Reverse Current V
IN
= 7V 0.1 mA
I
O
TRI-STATE Output Current V
O
= 2.5V 20 µA
V
O
= 0.5V −20 µA
V
CL
Input Clamp Voltage I
IN
= −18 mA −1.5 V
I
SC
Output Short-Circuit Current −30 −150 mA
I
CC
Power Supply Current All Outputs Disabled 35 60 mA
or Active
Switching Characteristics
V
CC
= 5V, T
A
= 25˚C
Symbol Parameter Conditions Min Typ Max Units
t
PLH
Input to Output C
L
=30pF 10 15 ns
t
PHL
Input to Output C
L
=30pF 10 15 ns
Skew Output to Output C
L
= 30 pF 2.0 6.0 ns
t
LZ
Enable to Output C
L
= 10 pF, S2 Open 15 35 ns
t
HZ
Enable to Output C
L
= 10 pF, S1 Open 15 25 ns
t
ZL
Enable to Output C
L
= 30 pF, S2 Open 20 30 ns
t
ZH
Enable to Output C
L
= 30 pF, S1 Open 20 30 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 TA= 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.
DS26LS31C/DS26LS31M
www.national.com 2
AC Test Circuit and Switching Time Waveforms
Typical Applications
DS005778-3
S1 and S2 of load circuit are closed except where shown.
FIGURE 1. AC Test Circuit
DS005778-4
f = 1 MHz, tr≤15 ns, tf≤6ns
FIGURE 2. Propagation Delays
DS005778-5
f = 1 MHz, tr≤15 ns, tf≤6ns
FIGURE 3. Enable and Disable Times
Two-Wire Balanced System, RS-422
DS005778-6
Note 6: RTis optional although highly recommended to reduce reflection.
DS26LS31C/DS26LS31M
www.national.com3
Typical Performance Characteristics
DS26LS31CN Unloaded I
C
vs Frequency vs T
A
DS005778-7
DS26LS31 I
CC
vs V
CC
vs T
A
DS005778-8
DS26LS31CN V
OH
vs I
OH
vs T
A
DS005778-9
DS26LS31CN V
OL
vs I
OL
vs T
A
DS005778-10
DS26LS31CN V
OD
vs I
O
vs T
A
DS005778-11
DS26LS31C/DS26LS31M
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Physical Dimensions inches (millimeters) unless otherwise noted
Small Outline Package (M)
Order Number DS26LS31CM
NS Package Number M16A
Molded Dual-In-Line Package (N)
Order Number DS26LS31CN
NS Package Number N16E
DS26LS31C/DS26LS31M
www.national.com5
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16 Lead Ceramic Flatpak (F)
Order Number DS26LS31MW/883
NS Package Number W16A
16 Lead Ceramic Dual-in-Line Package (J)
Order Number DS26LS31MJ/883
NS Package Number J16A
DS26LS31C/DS26LS31M
www.national.com 6
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
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DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
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into the body, or (b) support or sustain life, and
whose failure 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 reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
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www.national.com
20 Lead Ceramic Leadless Chip Carrier (E)
Order Number DS26LS31MJE/883
NS Package Number E20A
DS26LS31C/DS26LS31M Quad High Speed Differential Line Driver
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.
