SN74LS157
Quad 2-Input Multiplexer
The LSTTL/MSI SN74LS157 is a high speed Quad 2-Input
Multiplexer. Four bits of data from two sources can be selected using
the common Select and Enable inputs. The four buffered outputs
present the selected data in the true (non-inverted) form. The LS157
can also be used to generate any four of the 16 different functions of
two variables. The LS157 is fabricated with the Schottky barrier diode
process for high speed and is completely compatible with all
ON Semiconductor TTL families.
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•
•
•
•
•
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Schottky Process for High Speed
Multifunction Capability
Non-Inverting Outputs
Input Clamp Diodes Limit High Speed Termination Effects
Special Circuitry Ensures Glitch Free Multiplexing
ESD > 3500 Volts
LOW
POWER
SCHOTTKY
16
1
GUARANTEED OPERATING RANGES
Symbol
V
CC
T
A
I
OH
I
OL
Parameter
Supply Voltage
Operating Ambient
Temperature Range
Output Current – High
Output Current – Low
Min
4.75
0
Typ
5.0
25
Max
5.25
70
–0.4
8.0
Unit
V
°C
mA
mA
16
PLASTIC
N SUFFIX
CASE 648
1
SOIC
D SUFFIX
CASE 751B
16
1
SOEIAJ
M SUFFIX
CASE 966
ORDERING INFORMATION
Device
SN74LS157N
SN74LS157D
SN74LS157DR2
SN74LS157M
SN74LS157MEL
Package
16 Pin DIP
SOIC–16
SOIC–16
SOEIAJ–16
SOEIAJ–16
Shipping
2000 Units/Box
38 Units/Rail
2500/Tape & Reel
See Note 1
See Note 1
1. For ordering information on the EIAJ version of
the SOIC package, please contact your local
ON Semiconductor representative.
©
Semiconductor Components Industries, LLC, 2002
1
February, 2002 – Rev. 8
Publication Order Number:
SN74LS157/D
SN74LS157
V
CC
16
E
15
I
0c
14
I
1c
13
Z
c
12
I
0d
11
I
1d
10
Zd
9
NOTE:
The Flatpak version has the same
pinouts (Connection Diagram) as
the Dual In-Line Package.
1
S
2
I
0a
3
I
1a
4
Z
a
5
I
0b
6
I
1b
7
Z
b
8
GND
LOADING
(Note a)
PIN NAMES
S
E
I
0a
– I
0d
I
1a
– I
1d
Z
a
– Z
d
Common Select Input
Enable (Active LOW) Input
Data Inputs from Source 0
Data Inputs from Source 1
Multiplexer Outputs
HIGH
1.0 U.L.
1.0 U.L.
0.5 U.L.
0.5 U.L.
10 U.L.
LOW
0.5 U.L.
0.5 U.L.
0.25 U.L.
0.25 U.L.
5 U.L.
NOTES: a) 1 TTL Unit Load (U.L.) = 40
mA
HIGH/1.6 mA LOW.
Figure 1. Connection Diagram DIP
(TOP VIEW)
15 2 3 5 6 14 13 11 10
E I
0a
I
1a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
1
S
Z
a
Z
b
Z
c
Z
d
4
7
12
9
V
CC
= PIN 16
GND = PIN 8
Figure 2. Logic Symbol
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2
SN74LS157
2
3
5
6
14
13
11
10 15
1
4
7
12
9
V
CC
= PIN 16
GND = PIN 8
= PIN NUMBERS
Figure 3. Logic Diagram
FUNCTIONAL DESCRIPTION
The LS157 is a Quad 2-Input Multiplexer fabricated with
the Schottky barrier diode process for high speed. It selects
four bits of data from two sources under the control of a
common Select Input (S). The Enable Input (E) is active
LOW. When E is HIGH, all of the outputs (Z) are forced
LOW regardless of all other inputs.
The LS157 is the logic implementation of a 4-pole,
2-position switch where the position of the switch is
determined by the logic levels supplied to the Select Input.
The logic equations for the outputs are:
Z
a
= E
⋅
(I
1a
⋅
S + I
0a
⋅
S)
Z
c
= E
⋅
(I
1c
⋅
S + I
0c
⋅
S)
Z
b
= E
⋅
(I
1b
⋅
S + I
0b
⋅
S)
Z
d
= E
⋅
(I
1d
⋅
S + I
0d
⋅
S)
A common use of the LS157 is the moving of data from
two groups of registers to four common output busses. The
particular register from which the data comes is determined
by the state of the Select Input. A less obvious use is as a
function generator. The LS157 can generate any four of
the 16 different functions of two variables with one variable
common. This is useful for implementing highly irregular
logic.
TRUTH TABLE
SELECT
INPUT
S
X
H
H
L
L
I
0
X
X
X
L
H
ENABLE
E
H
L
L
L
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
INPUTS
I
1
X
L
H
X
X
OUTPUT
Z
L
L
H
L
H
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3
SN74LS157
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Limits
Symbol
V
IH
V
IL
V
IK
V
OH
Parameter
Input HIGH Voltage
Input LOW Voltage
Input Clamp Diode Voltage
Output HIGH Voltage
2.7
–0.65
3.5
0.25
V
OL
Output LOW Voltage
0.35
Input HIGH Current
I
0
, I
1
E, S
I
0
, I
1
E, S
I
IL
I
OS
I
CC
Input LOW Current
I
0
, I
1
E, S
Short Circuit Current (Note 2)
Power Supply Current
–20
0.5
20
40
0.1
0.2
–0.4
–0.8
–100
16
V
µA
0.4
Min
2.0
0.8
–1.5
Typ
Max
Unit
V
V
V
V
V
Test Conditions
Guaranteed Input HIGH Voltage for
All Inputs
Guaranteed Input LOW Voltage for
All Inputs
V
CC
= MIN, I
IN
= –18 mA
V
CC
= MIN, I
OH
= MAX, V
IN
= V
IH
or V
IL
per Truth Table
I
OL
= 4.0 mA
I
OL
= 8.0 mA
V
CC
= V
CC
MIN,
V
IN
= V
IL
or V
IH
per Truth Table
V
CC
= MAX, V
IN
= 2.7 V
I
IH
mA
V
CC
= MAX, V
IN
= 7.0 V
mA
mA
mA
V
CC
= MAX, V
IN
= 0.4 V
V
CC
= MAX
V
CC
= MAX
2. Not more than one output should be shorted at a time, nor for more than 1 second.
AC CHARACTERISTICS
(T
A
= 25°C)
Limits
Symbol
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
Parameter
Propagation Delay
Data to Output
Propagation Delay
Enable to Output
Propagation Delay
Select to Output
Min
Typ
9.0
9.0
13
14
15
18
Max
14
14
20
21
23
27
Unit
ns
ns
ns
Figure 2
Figure 1
Figure 2
V
CC
= 5.0 V
C
L
= 15 pF
Test Conditions
AC WAVEFORMS
V
IN
1.3 V
t
PHL
1.3 V
t
PLH
1.3 V
V
IN
1.3 V
t
PHL
1.3 V
t
PLH
1.3 V
V
OUT
1.3 V
V
OUT
1.3 V
Figure 1.
Figure 2.
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4
SN74LS157
PACKAGE DIMENSIONS
N SUFFIX
PLASTIC PACKAGE
CASE 648–08
ISSUE R
–A–
16
9
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEADS WHEN
FORMED PARALLEL.
4. DIMENSION B DOES NOT INCLUDE MOLD FLASH.
5. ROUNDED CORNERS OPTIONAL.
DIM
A
B
C
D
F
G
H
J
K
L
M
S
INCHES
MIN
MAX
0.740
0.770
0.250
0.270
0.145
0.175
0.015
0.021
0.040
0.70
0.100 BSC
0.050 BSC
0.008
0.015
0.110
0.130
0.295
0.305
0
_
10
_
0.020
0.040
MILLIMETERS
MIN
MAX
18.80
19.55
6.35
6.85
3.69
4.44
0.39
0.53
1.02
1.77
2.54 BSC
1.27 BSC
0.21
0.38
2.80
3.30
7.50
7.74
0
_
10
_
0.51
1.01
B
1
8
F
S
C
L
–T–
H
G
D
16 PL
SEATING
PLANE
K
J
T A
M
M
0.25 (0.010)
M
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5
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