MC74AC257 Datasheet, PDF (1/8 Pages) ON Semiconductor – Quad 2−Input Multiplexer with 3−State Outputs

MC74AC257
MC74ACT257
Quad 2ĆInput Multiplexer
with 3ĆState Outputs
The MC74AC257/74ACT257 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 (noninverted) form. The
outputs may be switched to a high impedance state by placing a logic HIGH on
the common Output Enable (OE) input, allowing the outputs to interface directly
with bus-oriented systems.
• Multiplexer Expansion by Tying Outputs Together
• Noninverting 3-State Outputs
• Outputs Source/Sink 24 mA
• ′ACT257 Has TTL Compatible Inputs
VCC OE I0c I1c Zc I0d I1d Zd
16 15 14 13 12 11 10 9
QUAD 2-INPUT
MULTIPLEXER WITH
3-STATE OUTPUTS
N SUFFIX
CASE 648-08
PLASTIC
12345678
S I0a I1a Za I0b I1b Zb GND
PIN NAMES
S
OE
I0a–I0d
I1a–I1d
Za–Zd
Common Data Select Input
3-State Output Enable Input
Data Inputs from Source 0
Data Inputs from Source 1
3-State Multiplexer Outputs
TRUTH TABLE
Output
Enable
Select
Input
OE
S
H
X
L
H
L
H
L
L
L
L
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Z = High Impedance
Data
Inputs
I0
I1
X
X
X
L
X
H
L
X
H
X
Outputs
Z
Z
L
H
L
H
D SUFFIX
CASE 751B-05
PLASTIC
LOGIC SYMBOL
OE I0a I1a I0b I1b I0c I1c I0d I1d
S
Za Zb Zc Zd
FACT DATA
5-1