DS26C31M,DS26C31T
DS26C31T/DS26C31M CMOS Quad TRI-STATE Differential Line Driver
Literature Number: SNLS375A
DS26C31T/DS26C31M
CMOS Quad TRI-STATE®Differential Line Driver
General Description
The DS26C31 is a quad differential line driver designed for
digital data transmission over balanced lines. The
DS26C31T meets all the requirements of EIA standard RS-
422 while retaining the low power characteristics of CMOS.
The DS26C31M is compatible with EIA standard RS-422;
however, one exception in test methodology is taken (Note
8). This enables the construction of serial and terminal inter-
faces while maintaining minimal power consumption.
The DS26C31 accepts TTL or CMOS input levels and trans-
lates these to RS-422 output levels. This part uses special
output circuitry that enables the drivers to power down with-
out loading down the bus. This device has enable and dis-
able circuitry common to all four drivers. The DS26C31 is pin
compatible to the AM26LS31 and the DS26LS31.
All inputs are protected against damage due to electrostatic
discharge by diodes to V
CC
and ground.
Features
nTTL input compatible
nTypical propagation delays: 6 ns
nTypical output skew: 0.5 ns
nOutputs will not load line when V
CC
=0V
nDS26C31T meets the requirements of EIA standard
RS-422
nOperation from single 5V supply
nTRI-STATE outputs for connection to system buses
nLow quiescent current
nAvailable in surface mount
nMil-Std-883C compliant
Connection Diagrams
Dual-In-Line Package
00857401
Top View
Order Number DS26C31TM or DS26C31TN
See NS Package Number M16A or N16E
For Complete Military Product Specifications,
refer to the appropriate SMD or MDS.
Order Number DS26C31ME/883, DS26C31MJ/883
or DS26C31MW/883
See NS Package Number E20A, J16A or W16A
20-Lead Ceramic Leadless Chip Carrier (E)
00857412
Truth Table
ENABLE ENABLE Input Non-Inverting Inverting
Output Output
LHX Z Z
All other L L H
combinations of H H L
enable inputs
L = Low logic state
X = Irrelevant
H = High logic state
Z = TRI-STATE (high impedance)
TRI-STATE®is a registered trademark of National Semiconductor Corporation.
FACT™is a trademark of National Semiconductor Corporation.
June 1998
DS26C31T/DS26C31M CMOS Quad TRI-STATE Differential Line Driver
© 2004 National Semiconductor Corporation DS008574 www.national.com
Absolute Maximum Ratings (Notes 1,
2)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
Supply Voltage (V
CC
) −0.5V to 7.0V
DC Input Voltage (V
IN
) −1.5V to V
CC
+1.5V
DC Output Voltage (V
OUT
) −0.5V to 7V
Clamp Diode Current (I
IK
,I
OK
)±20 mA
DC Output Current, per pin (I
OUT
)±150 mA
DC V
CC
or GND Current,
per pin (I
CC
)±150 mA
Storage Temperature Range (T
STG
) −65˚C to +150˚C
Max. Power Dissipation (P
D
)@25˚C (Note 3)
Ceramic “J” Pkg. 2419 mW
Plastic “N” Pkg. 1736 mW
SOIC “M” Pkg. 1226 mW
Ceramic “W” Pkg. 1182 mW
Ceramic “E” Pkg. 2134 mW
Lead Temperature (T
L
)
(Soldering, 4 sec.) 260˚C
This device does not meet 2000V ESD Rating. (Note 13)
Operating Conditions
Min Max Units
Supply Voltage (V
CC
) 4.50 5.50 V
DC Input or Output Voltage
(V
IN
,V
OUT
)0V
CC
V
Operating Temperature Range (T
A
)
DS26C31T −40 +85 ˚C
DS26C31M −55 +125 ˚C
Input Rise or Fall Times (t
r
,t
f
) 500 ns
DC Electrical Characteristics
V
CC
=5V±10% (unless otherwise specified) (Note 4)
Symbol Parameter Conditions Min Typ Max Units
V
IH
High Level Input Voltage 2.0 V
V
IL
Low Level Input Voltage 0.8 V
V
OH
High Level Output Voltage V
IN
=V
IH
or V
IL
, 2.5 3.4 V
I
OUT
= −20 mA
V
OL
Low Level Output V
IN
=V
IH
or V
IL
, 0.3 0.5 V
Voltage I
OUT
=20mA
V
T
Differential Output R
L
= 100Ω2.0 3.1 V
Voltage (Note 5)
|V
T
|−|V
T
| Difference In R
L
= 100Ω0.4 V
Differential Output (Note 5)
V
OS
Common Mode R
L
= 100Ω1.8 3.0 V
Output Voltage (Note 5)
|V
OS
−V
OS
| Difference In R
L
= 100Ω0.4 V
Common Mode Output (Note 5)
I
IN
Input Current V
IN
=V
CC
, GND, V
IH
,orV
IL
±1.0 µA
I
CC
Quiescent Supply DS26C31T V
IN
=V
CC
or GND 200 500 µA
Current (Note 6) I
OUT
=0µA V
IN
= 2.4V or 0.5V 0.8 2.0 mA
(Note 6)
DS26C31M V
IN
=V
CC
or GND 200 500 µA
I
OUT
=0µA V
IN
= 2.4V or 0.5V 0.8 2.1 mA
(Note 6)
I
OZ
TRI-STATE Output V
OUT
=V
CC
or GND
Leakage Current ENABLE = V
IL
±0.5 ±5.0 µA
ENABLE = V
IH
I
SC
Output Short V
IN
=V
CC
or GND −30 −150 mA
Circuit Current (Notes 5, 7)
I
OFF
Output Leakage Current DS26C31T V
OUT
= 6V 100 µA
Power Off (Note 5) V
CC
=0V V
OUT
= −0.25V −100 µA
DS26C31M V
OUT
= 6V 100 µA
V
CC
=0V V
OUT
= 0V −100 µA
(Note 8)
DS26C31T/DS26C31M
www.national.com 2
DC Electrical Characteristics (Continued)
Note 1: Absolute Maximum Ratings are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device
should be operated at these limits. The table of “Electrical Characteristics” provide conditions for actual device operation.
Note 2: Unless otherwise specified, all voltages are referenced to ground. All currents into device pins are positive, all currents out of device pins are negative.
Note 3: Ratings apply to ambient temperature at 25˚C. Above this temperature derate N package at 13.89 mW/˚C, J package 16.13 mW/˚C, M package
9.80 mW/˚C, E package 12.20 mW/˚C, and W package 6.75 mW/˚C.
Note 4: Unless otherwise specified, min/max limits apply across the recommended operating temperature range. All typicals are given for VCC = 5V and TA= 25˚C.
Note 5: See EIA Specification RS-422 for exact test conditions.
Note 6: Measured per input. All other inputs at VCC or GND.
Note 7: This is the current sourced when a high output is shorted to ground. Only one output at a time should be shorted.
Note 8: The DS26C31M (−55˚C to +125˚C) is tested with VOUT between +6V and 0V while RS-422A condition is +6V and −0.25V.
Switching Characteristics
V
CC
=5V±10%, t
r
≤6 ns, t
f
≤6ns(Figures 1, 2, 3, 4) (Note 4)
Symbol Parameter Conditions Min Typ Max Units
DS26C31T CS26C31M
t
PLH
,t
PHL
Propagation Delays S1 Open 2 6 11 14 ns
Input to Output
Skew (Note 9) S1 Open 0.5 2.0 3.0 ns
t
TLH
,t
THL
Differential Output Rise S1 Open 6 10 14 ns
And Fall Times
t
PZH
Output Enable Time S1 Closed 11 19 22 ns
t
PZL
Output Enable Time S1 Closed 13 21 28 ns
t
PHZ
Output Disable Time S1 Closed 5 9 12 ns
(Note 10)
t
PLZ
Output Disable Time S1 Closed 7 11 14 ns
(Note 10)
C
PD
Power Dissipation 50 pF
Capacitance (Note 11)
C
IN
Input Capacitance 6 pF
Note 9: Skew is defined as the difference in propagation delays between complementary outputs at the 50% point.
Note 10: Output disable time is the delay from ENABLE or ENABLE being switched to the output transistors turning off. The actual disable times are less than
indicated due to the delay added by the RC time constant of the load.
Note 11: CPD determines the no load dynamic power consumption, PD=C
PD VCC2f+I
CC VCC, and the no load dynamic current consumption, IS=C
PD VCC f+
ICC.
Comparison Table of Switching Characteristics into “LS-Type” Load
V
CC
= 5V, T
A
= 25˚C, t
r
≤6 ns, t
f
≤6ns(Figures 2, 4, 5, 6) (Note 12)
Symbol Parameter Conditions DS26C31T DS26LS31C Units
Typ Max Typ Max
t
PLH
,t
PHL
Propagation Delays C
L
=30pF
Input to Output S1 Closed 6 8 10 15 ns
S2 Closed
Skew (Note 9) C
L
=30pF
S1 Closed 0.5 1.0 2.0 6.0 ns
S2 Closed
t
THL
,t
TLH
Differential Output Rise C
L
=30pF
and Fall Times S1 Closed 4 6 ns
S2 Closed
t
PLZ
Output Disable Time C
L
=10pF
(Note 10) S1 Closed 6 9 15 35 ns
S2 Open
DS26C31T/DS26C31M
www.national.com3
Comparison Table of Switching Characteristics into “LS-Type”
Load (Continued)
V
CC
= 5V, T
A
= 25˚C, t
r
≤6 ns, t
f
≤6ns(Figures 2, 4, 5, 6) (Note 12)
Symbol Parameter Conditions DS26C31T DS26LS31C Units
Typ Max Typ Max
t
PHZ
Output Disable Time C
L
=10pF
(Note 10) S1 Open 4 7 15 25 ns
S2 Closed
t
PZL
Output Enable Time C
L
=30pF
S1 Closed 14 20 20 30 ns
S2 Open
t
PZH
Output Enable Time C
L
=30pF
S1 Open 11 17 20 30 ns
S2 Closed
Note 12: This table is provided for comparison purposes only. The values in this table for the DS26C31 reflect the performance of the device but are not tested or
guaranteed.
Note 13: ESD Rating:
HBM (1.5 kΩ, 100 pF)
Inputs ≥1500V
Outputs ≥1000V
EIAJ (0Ω, 200 pF) ≥350V
Logic Diagram
00857402
AC Test Circuit and Switching
Time Waveforms
00857403
Note: C1 = C2 = C3 = 40 pF (Including Probe and Jig Capacitance), R1 = R2 = 50Ω,R3=500Ω.
FIGURE 1. AC Test Circuit
DS26C31T/DS26C31M
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AC Test Circuit and Switching Time Waveforms (Continued)
00857404
FIGURE 2. Propagation Delays
00857405
FIGURE 3. Enable and Disable Times
00857407
Input pulse;f=1MHz, 50%; tr≤6 ns, tf≤6ns
FIGURE 4. Differential Rise and Fall Times
DS26C31T/DS26C31M
www.national.com5
AC Test Circuit and Switching Time Waveforms (Continued)
Typical Applications
Two-Wire Balanced System, RS-422
00857409
*RTis optional although highly recommended to reduce reflection.
00857406
FIGURE 5. Load AC Test Circuit for “LS-Type” Load
00857408
FIGURE 6. Enable and Disable Times for “LS-Type” Load
DS26C31T/DS26C31M
www.national.com 6
Typical Performance Characteristics
Differential Propagation Delay
vs Temperature
Differential Propagation Delay
vs Power Supply Voltage
00857414 00857415
Differential Skew vs
Temperature
Differential Skew vs Power
Supply Voltage
00857416 00857417
Differential Transition Time
vs Temperature
Differential Transition Time
vs Power Supply Voltage
00857418 00857419
DS26C31T/DS26C31M
www.national.com7
Typical Performance Characteristics (Continued)
Complementary Skew vs
Temperature
Complementary Skew vs
Power Supply Voltage
00857420 00857421
Differential Output Voltage
vs Output Current
Differential Output Voltage
vs Output Current
00857422 00857423
Output High Voltage vs
Output High Current
Output High Voltage vs
Output High Current
00857424 00857425
DS26C31T/DS26C31M
www.national.com 8
Typical Performance Characteristics (Continued)
Output Low Voltage vs
Output Low Current
Output Low Voltage vs
Output Low Current
00857426 00857427
Supply Current
vs Temperature
Output Low Voltage vs
Output Low Current
00857428 00857426
Output Low Voltage vs
Output Low Current
Supply Current
vs Temperature
00857427 00857428
DS26C31T/DS26C31M
www.national.com9
Typical Performance Characteristics (Continued)
Supply Current vs
Power Supply Voltage
No Load Supply Current
vs Data Rate
00857429 00857430
Loaded Supply Current
vs Data Rate
Output Short Circuit Current
vs Temperature
00857431 00857432
Output Short Circuit Current
vs Power Supply Voltage
00857433
DS26C31T/DS26C31M
www.national.com 10
Physical Dimensions inches (millimeters)
unless otherwise noted
20-Lead Ceramic Leadless Chip Carrier (E)
Order Number DS26C31ME/883
NS Package Number E20A
16-Lead Ceramic Dual-In-Line Package (J)
Order Number DS26C31MJ/883
NS Package Number J16A
DS26C31T/DS26C31M
www.national.com11
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
Molded Package Small Outline (M)
Order Number DS26C31TM
NS Package Number M16A
16-Lead Molded Dual-In-Line Package (N)
Order Number DS26C31TN
NS Package Number N16E
DS26C31T/DS26C31M
www.national.com 12
Physical Dimensions inches (millimeters) unless otherwise noted (Continued)
16-Lead Ceramic Flatpak Package (W)
Order Number DS26C31MW/883
NS Package Number W16A
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www.national.com
DS26C31T/DS26C31M CMOS Quad TRI-STATE 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.
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