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Philips Semiconductors
Product specification
74ALS157/74ALS158
Data selector/multiplexer
74ALS157 Quad 2-input data selector/multiplexer, non-inverting
74ALS158 Quad 2-input data selector/multiplexer, inverting
2
1991 Feb 08
853–1129 01670
DESCRIPTION
The 74ALS157 is a quad 2-input multiplexer which selects 4 bits of
data from one of two sources under the control of a common select
input (S). The enable input (E) is active when Low. When E is High,
all of the outputs (Yn) are forced Low regardless of all other input
conditions.
Moving data from two registers to a common output bus is a typical
use of the 74ALS157. The state of the select input determines the
particular register from which data comes.
The device is the logic implementation of 4-pole, 2-position switch
where the position of the switch is determined by the logic levels
supplied to the select input. The 74ALS158 is similar but has
inverting outputs (Yn).
TYPE
TYPICAL
PROPAGATION DELAY
TYPICAL
SUPPLY CURRENT
(TOTAL)
74ALS157
6.0ns
6mA
74ALS158
6.0ns
6mA
ORDERING INFORMATION
ORDER CODE
DESCRIPTION
COMMERCIAL RANGE
V
CC
= 5V
±
10%,
T
amb
= 0
°
C to +70
°
C
DRAWING
NUMBER
16-pin plastic DIP
74ALS157N, 74ALS158N
SOT38-4
16-pin plastic SO
74ALS157D, 74ALS158D
SOT109-1
INPUT AND OUTPUT LOADING AND FAN-OUT TABLE
PINS
DESCRIPTION
74ALS (U.L.)
HIGH/LOW
LOAD VALUE
HIGH/LOW
Ina, Inb, Inc, Ind
Data inputs
1.0/1.0
20
μ
A/0.1mA
20
μ
A/0.1mA
20
μ
A/0.1mA
S
Select input
1.0/1.0
E
Enable input
1.0/1.0
Ya – Yd, Ya – Yd
NOTE:
One (1.0) ALS unit load is defined as: 20
μ
A in the High state and 0.1mA in the Low state.
Data outputs
20/240
0.4mA/24mA
PIN CONFIGURATION – 74ALS157
16
15
14
13
12
11
10
7
6
5
4
3
2
1
Yb
V
CC
Yd
I0c
I1c
I1d
E
I0d
S
I0a
I1b
I1a
Ya
I0b
9
8
GND
Yc
SC00051
PIN CONFIGURATION – 74ALS158
16
15
14
13
12
11
10
7
6
5
4
3
2
1
Yb
V
CC
Yd
I0c
I1c
I1d
E
I0d
S
I0a
I1b
I1a
Ya
I0b
9
8
GND
Yc
SC00052
LOGIC SYMBOL – 74ALS157
V
= Pin 16
GND = Pin 8
SC00053
1
15
S
E
2
3
5
6
11
10
14
I0a
I1a
I0b
I1b
I0c
I1c
I0d
Ya
Yb
Yc
Yd
4
7
9
12
13
I1d
LOGIC SYMBOL – 74ALS158
V
= Pin 16
GND = Pin 8
SC00054
1
15
S
E
2
3
5
6
11
10
14
I0a
I1a
I0b
I1b
I0c
I1c
I0d
Ya
Yb
Yc
Yd
4
7
9
12
13
I1d