ST26C31B
CMOS quad 3-state differential line driver
Features
■ TTL input compatible
■ Typical propagation delay: 6 ns
■ Typical output skew: 0.5 ns
■ Output will not load line when VCC = 0 V
■ Meets the requirements of EIA standard DIP-16 SO-16
RS-422
■ Operation from single 5 V supply
■ 3-state outputs for connection to system buses
■ Low quiescent current
■ Available in surface mount
TSSOP16
Description
The ST26C31B is a quad differential line driver
designed for digital data transmission over
balanced lines and meets all the requirements of
EIA standard RS-422 while retaining the low
power characteristics of CMOS.
The ST26C31B accepts TTL or CMOS input
levels and translates these to RS-422 output
levels. This part uses special outputs circuitry
common to all four drivers. All outputs are
protected against damage due to electrostatic
discharge by diode to VCC and ground.
Table 1. Device summary
Order codes Temperature range Package Packaging
ST26C31BN -40 to 85 °C DIP-16 25 parts per tube / 40 tube per box
ST26C31BDR -40 to 85 °C SO-16 (tape and reel) 2500 parts per reel
ST26C31BTR -40 to 85 °C TSSOP16 (tape and reel) 2500 parts per reel
June 2008 Rev 8 1/15
www.st.com 15
Contents ST26C31B
Contents
1 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
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ST26C31B Pin configuration
1 Pin configuration
Figure 1. Pin connections
Table 2. Pin description
Pin n° Symbol Name and function
1 AIN Input A
2 AOUT Channel A output
3 AOUT Channel A output
4 EN ENABLE
5 BOUT Channel B output
6 BOUT Channel B output
7 BIN Input B
8 GND Ground
9 CIN Input C
10 COUT Channel C output
11 COUT Channel C output
12 EN ENABLE
13 DOUT Channel D output
14 DOUT Channel D output
15 DIN Input D
16 VCC Supply voltage
3/15
Pin configuration ST26C31B
Table 3. Truth table
Enable Enable Input Output Output
L H X Z Z
L L H
All other combinations of enable inputs
H H L
Note: L = Low voltage state
H = High logic state
X = Don’t care
Z = High impedance
4/15
ST26C31B Maximum ratings
2 Maximum ratings
Table 4. Absolute maximum ratings (1) (2)
Symbol Parameter Value Unit
VCC Supply voltage -0.5 to 7 V
VIN DC input voltage -0.5 to (VCC + 0.5) V
VOUT DC output voltage (high or low state) -0.5 to 7 V
IIK Clamp diode current ± 20 mA
IOUT DC output current per pin ± 150 mA
ICC DC VCC or gnd current ± 150 mA
TSTG Storage temperature range -65 to +150 °C
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.
2. Unless otherwise specified, all voltage are referenced to ground. All currents into the device pins are positive; all currents
out of the device pins are negative.
Table 5. Recommended operating conditions
Symbol Parameter Value Unit
VCC Supply voltage 4.5 to 5.5 V
VIN DC input voltage 0 to VCC V
VOUT DC output voltage (high or low state) 0 to VCC V
VOUT DC output voltage (VCC = 0 V or high impedance) 0 to 5 V
TA Operating temperature range -40 to +85 °C
tr, tf Maximum enable input rise or fall times 500 ns
5/15
Electrical characteristics ST26C31B
3 Electrical characteristics
Table 6. Electrical characteristics (VCC = 5 V ± 10 %, unless otherwise specified (1))
Value
Symbol Parameter Test conditions Unit
Min. Typ. Max.
VIH High level input voltage 2 V
VIL Low level input voltage 0.8 V
VOH High level output voltage VIN = VIH or VIL, IOUT = -20mA 2.5 3.4 V
VOL Low level output voltage VIN = VIH or VIL, IOUT = +20mA 0.3 0.5 V
(2)
VT Differential output voltage RL = 100 Ω 2 3.1 V
Difference in differential
VT-VT RL = 100 Ω (2) 0.4 V
output voltage
Common mode output
VOS RL = 100 Ω (2) 1.8 3 V
voltage
VOS- Difference in common
RL = 100 Ω (2) 0.4 V
VOS mode output voltage
IIN Input current VIN = VCC, GND, VIH or VIL ±1 µA
Quiescent supply current VIN = VCC or GND 200 500 µA
ICC (2) IOUT = 0 µA
(3)
VIN = 2.4 or 0.5 V 0.8 2 mA
3-state output leakage VOUT = VCC or GND
IOZ ±0.5 ±5 µA
current ENABLE = VIL ENABLE = VIH
Output short circuit VIN = VCC or GND
ISC (2) (4) -30 -150 mA
current
Power off output leakage VOUT = 6 V 100 µA
IOFF VCC = 0 V
current (2) VOUT = -0.25 V -100 µA
1. Unless otherwise specified, min./max. limits apply across the recommended operating temperature range. All typical are
given for VCC = 5 V and TA = 25 °C
2. See EIA Specification RS422 for exact test conditions.
3. Measured per pin input. All other input at VCC or GND.
4. This is the current sourced when a high output is shorted to ground. Only one output at time should be shorted.
6/15
ST26C31B Electrical characteristics
Table 7. Switching characteristics (VCC = 5 V ± 10 %, tr = tf ≤ 6 ns (1))
Value
Symbol Parameter Test conditions Unit
Min. Typ. Max.
tPLH
Propagation delay input to output S1 Open 2 6 11 ns
tPHL
(2)
Skew S1 Open 0.5 2 ns
tTLH
Differential output rise and fall times S1 Open 6 10 ns
tTHL
tPZH Output enable time S1 Closed 11 19 ns
tPZL Output enable time S1 Closed 13 21 ns
(3)
tPHZ Output disable time S1 Closed 5 9 ns
tPLZ (3)
Output disable time S1 Closed 7 11 ns
CPD Power dissipation capacitance (4) 50 pF
CIN Input capacitance 6 pF
1. Unless otherwise specified, min./max. limits apply across the recommended operating temperature range. All typical are
given for VCC = 5 V and TA = 25 °C
2. Skew is defined as the difference in propagation delays between complementary outputs at the 50 % point.
3. Output disable time is the delay from the control input being switched to the output transistors tuning off. The actual disable
times are less than indicated due to the delay added by RC time constant of the load.
4. CPD determines the no load dynamic power consumption, PD = CPDVCC2, f = ICCVCC, and the no load dynamic current
consumption, PD = CPD VCCf + ICC .
7/15
Package mechanical data ST26C31B
4 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com
8/15
ST26C31B Package mechanical data
Plastic DIP-16 (0.25) mechanical data
mm. inch.
Dim.
Min. Typ. Max. Min. Typ. Max.
a1 0.51 0.020
B 0.77 1.65 0.030 0.065
b 0.5 0.020
b1 0.25 0.010
D 20 0.787
E 8.5 0.335
e 2.54 0.100
e3 17.78 0.700
F 7.1 0.280
I 5.1 0.201
L 3.3 0.130
Z 1.27 0.050
P001C
9/15
Package mechanical data ST26C31B
SO-16 mechanical data
mm. inch.
Dim.
Min. Typ. Max. Min. Typ. Max.
A 1.75 0.068
a1 0.1 0.25 0.004 0.010
a2 1.64 0.063
b 0.35 0.46 0.013 0.018
b1 0.19 0.25 0.007 0.010
C 0.5 0.019
c1 45° (typ.)
D 9.8 10 0.385 0.393
E 5.8 6.2 0.228 0.244
e 1.27 0.050
e3 8.89 0.350
F 3.8 4.0 0.149 0.157
G 4.6 5.3 0.181 0.208
L 0.5 1.27 0.019 0.050
M 0.62 0.024
S 8° (max.)
0016020D
10/15
ST26C31B Package mechanical data
TSSOP16 mechanical data
mm. inch.
Dim.
Min. Typ. Max. Min. Typ. Max.
A 1.2 0.047
A1 0.05 0.15 0.002 0.004 0.006
A2 0.8 1 1.05 0.031 0.039 0.041
b 0.19 0.30 0.007 0.012
c 0.09 0.20 0.004 0.0079
D 4.9 5 5.1 0.193 0.197 0.201
E 6.2 6.4 6.6 0.244 0.252 0.260
E1 4.3 4.4 4.48 0.169 0.173 0.176
e 0.65 BSC 0.0256 BSC
K 0° 8° 0° 8°
L 0.45 0.60 0.75 0.018 0.024 0.030
A A2
K L
A1 b e
c E
E1
PIN 1 IDENTIFICATION
1
0080338D
11/15
Package mechanical data ST26C31B
Tape & reel SO-16 mechanical data
mm. inch.
Dim.
Min. Typ. Max. Min. Typ. Max.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.45 6.65 0.254 0.262
Bo 10.3 10.5 0.406 0.414
Ko 2.1 2.3 0.082 0.090
Po 3.9 4.1 0.153 0.161
P 7.9 8.1 0.311 0.319
12/15
ST26C31B Package mechanical data
Tape & reel TSSOP16 mechanical data
mm. inch.
Dim.
Min. Typ. Max. Min. Typ. Max.
A 330 12.992
C 12.8 13.2 0.504 0.519
D 20.2 0.795
N 60 2.362
T 22.4 0.882
Ao 6.7 6.9 0.264 0.272
Bo 5.3 5.5 0.209 0.217
Ko 1.6 1.8 0.063 0.071
Po 3.9 4.1 0.153 0.161
P 7.9 8.1 0.311 0.319
13/15
Revision history ST26C31B
5 Revision history
Table 8. Document revision history
Date Revision Changes
02-May-2006 7 Order codes updated.
12-Jun-2008 8 Added: Table 1 on page 1.
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ST26C31B
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