4-127
FAST AND LS TTL DATA
QUAD 2-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
The MC74F257 is a quad 2-input multiplexer with 3-state outputs. Four bits
of data from two sources can be selected using a common Data Select input.
The four outputs present the selected data in true (non-inverted) form. The
outputs may be switched to a high impedance state with a HIGH on the com-
mon Output Enable (OE) input, allowing the outputs to interface directly with
bus oriented systems.
? Multiplexer Expansion by Tying Outputs Together
? Non-Inverting 3-State Outputs
? Input Clamp Diodes Limit High-Speed Termination Effects
? AC Enhanced Version of the F257
CONNECTION DIAGRAM
1516 14 13 12 11 10
21 3 4 5 6 7
V
CC
9
8
GND
OE I
0c
I
1c
Z
c
I
0d
I
1d
S I
0a
I
1a
Z
a
I
0b
I
1b
Z
b
Z
d
LOGIC DIAGRAM
Z
a
Z
b
Z
c
Z
d
OE I
0a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
SI
1a
FUNCTION TABLE
Output
Enable
Select
Input
Data
Inputs Outputs
OE S I
0
I
1
Z
H X X X Z
L H X L L
L H X H H
L L L X L
L L H X H
N SUFFIX
PLASTIC
CASE 648-08
16
1
J SUFFIX
CERAMIC
CASE 620-09
16
1
MC54FXXXAJ Ceramic
MC74FXXXAN Plastic
MC74FXXXAD SOIC
MC74F257A
QUAD 2-INPUT MULTIPLEXER
WITH 3-STATE OUTPUTS
FAST? SCHOTTKY TTL
ORDERING INFORMATION
16
1
D SUFFIX
SOIC
CASE 751B-03
LOGIC SYMBOL
V
CC
= PIN 16
GND = PIN 8
1
15
2
3
5
6
14
13
11
10
S
OE
I
0a
I
1a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
4
7
12
9
Z
a
Z
b
Z
c
Z
d
H = HIGH Voltage Level
L = LOW Voltage Level
X = Don’t Care
Z = High Impedance
