ST26C31
...the analog plus company
TM
Quad RS-422 CMOS
Differential Line Driver
June 1997-3
FEATURES
D
Pin-to-Pin Compatible with National DS26C31C
D
Low Power CMOS Design
D
Three-State Outputs with Enable Pin
D
Meets the EIA RS-422 Requirements
D
Low Propagation Delays
D
High Speed
GENERAL DESCRIPTION
The ST26C31 is a CMOS quad differential line driver
designed to meet the standard RS-422 requirements and
digital data transmission over balanced lines. To improve
noise margin and output stability for slow changing input
signals, special hysteresis is built in the ST26C31 circuit.
The ST26C31 is a high speed CMOS line driver designed
to operate with MFM / RLL controllers and hard disk
drives as well as RS-422 digital data transmission
applications. ST26C31 is suitable for low power 5V
operation with high input voltage protection devices.
ORDERING INFORMATION
Part No.
ST26C31CP16
ST26C31CF16
ST26C31IP16
ST26C31IF16
Package
16 Lead 300 Mil PDIP
16 Lead 150 Mil JEDEC SOIC
16 Lead 300 Mil PDIP
16 Lead 150 Mil JEDEC SOIC
Operating
Temperature Range
0°C to +70°C
0°C to +70°C
-40°C to +85°C
-40°C to +85°C
INPUT A
INPUT D
OUTPUT A+
OUTPUT A-
OUTPUT D+
OUTPUT D-
ENABLE
-ENABLE
OUTPUT B-
OUTPUT B+
OUTPUT C-
OUTPUT C+
INPUT B
INPUT C
Figure 1. Block Diagram
Rev. 1.01
E1991
EXAR Corporation, 48720 Kato Road, Fremont, CA 94538
z
(510) 668-7000
z
FAX (510) 668-7017
1
ST26C31
PIN CONFIGURATION
INPUT A
OUTPUT A+
OUTPUT A-
ENABLE
OUTPUT B-
OUTPUT B+
INPUT B
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
INPUT D
OUTPUT D+
OUTPUT D-
-ENABLE
OUTPUT C-
OUTPUT C+
INPUT C
INPUT A
OUTPUT A+
OUTPUT A-
ENABLE
OUTPUT B-
OUTPUT B+
INPUT B
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
INPUT D
OUTPUT D+
OUTPUT D-
-ENABLE
OUTPUT C-
OUTPUT C+
INPUT C
16 Lead PDIP (0.300”)
16 Lead SOIC (Jedec, 0.150”)
PIN DESCRIPTION
Pin #
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
Symbol
INPUT A
OUTPUT A+
OUTPUT A-
ENABLE
OUTPUT B-
OUTPUT B+
INPUT B
GND
INPUT C
OUTPUT C+
OUTPUT C-
-ENABLE
OUTPUT D-
OUTPUT D+
INPUT D
V
CC
Type
I
O
O
I
O
O
I
O
I
O
O
I
O
O
I
I
Description
Driver A input pin.
Driver A differential non-inverting output pin.
Driver A differential inverting output pin.
Gate control (active high). This pin is one of the two control pins which enables or disables
all four drivers. All four drivers are gated with two input or gate.
Driver B differential inverting output pin.
Driver B differential non-inverting output pin.
Driver B input pin.
Signal and power ground.
Driver C input pin.
Driver C differential non-inverting output pin.
Driver C differential inverting output pin.
Gate control (active low). See ENABLE pin description.
Driver D differential inverting output pin.
Driver D differential non-inverting output pin.
Driver D input pin.
Power supply pin.
Rev. 1.01
2
ST26C31
AC ELECTRICAL CHARACTERISTICS
Test Conditions: T
A
= -40°C - +85°C, V
CC
= 5.0V + 10% unless otherwise specified.
Symbol
T
1
T
2
T
3
T
4
T
51
Note
1
Skew
Parameter
Propagation Delay, Input to
Output
Differential Output Rise and Fall
Time
Output Enable Time
Output Disable Time
Skew
Min.
Typ.
8
8
18
18
Max.
10
10
20
20
2
Unit
ns
ns
ns
ns
ns
Conditions
S1 open
S1 open
S1 close
S1 close
S1 open
is defined as the difference in propagation delays between complementary outputs at the 50% point.
DC ELECTRICAL CHARACTERISTICS
Test Conditions: T
A
= -40°C - +85°C, V
CC
= 5.0V + 10% unless otherwise specified.
Symbol
I
IN
I
CC
I
OZ
V
IH
V
IL
V
OH
V
OL
V
OS
V
OC
V
OD
C
IN
C
PD
I
OS
I
OFF
Parameter
Input Current
Operating Current
Three-State Output Leakage
Input High Level
Input Low Level
Output High Level
Output Low Level
Differential Output Level
Common Mode Output Voltage
Difference in Common Mode
Output
Input Capacitance
Power Dissipation Capacitance
Output Short Current
Output Leakage Current Power
Off
Output Current
-200
7
10
100
-30
100
-100
I
DC
+150
2.0
3.0
0.4
15
pF
pF
mA
mA
mA
mA
V
I
N
=V
CC
or GND
V
OUT
=6V
V
OUT
=0.25V
2.5
0.5
2.0
0.8
600
+2.0
Min.
Typ.
Max.
+1.0
Unit
mA
mA
mA
V
V
V
V
V
V
R
L
=100W
R
L
=100W
R
L
=100W
Conditions
Specifications are subject to change without notice
Rev. 1.01
3
ST26C31
ABSOLUTE MAXIMUM RATINGS
Supply Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V
Voltage at Any Pin . . . . . . . . GND-0.3V to V
CC
+ 0.3V
Operating Temperature . . . . . . . . . . . –40°C to +85°C
Storage Temperature . . . . . . . . . . . . -60°C to +160°C
Package Dissipation . . . . . . . . . . . . . . . . . . . . . 500mW
Enable
-Enable
Input
Differential
Non-Inverting
Output
Z
L
H
L
H
L
H
Differential
Inverting
Output
Z
H
L
H
L
H
L
L
L
L
H
H
H
H
H
L
L
L
L
H
H
X
L
H
L
H
L
H
Notes
X = Don’t care
Z = Three-State (high impedance)
Table 1. Functional Table
V
CC
U1
-ENABLE
Input
C2
40pF
C1
40pF
Driver
C3
40pF
R2
50
R1
50
R3
500
S1
Figure 2. Test Condition
Rev. 1.01
4
ST26C31
ENABLE
-ENABLE
INPUT X
T
3
OUTPUT X+
T
3
OUTPUT X-
90%
10%
T
2
10%
T
4
T
1
T
1
T
4
90%
T
1
T
1
T
2
OUTPUT X+
50%
T
5
OUTPUT X-
50%
Figure 3. Differential Line Driver Timing
Rev. 1.01
5
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