IN74ACT251
8-INPUT DATA SELECTOR/MULTIPLEXER
WITH 3-STATE OUTPUTS
High-Speed Silicon-Gate CMOS
The IN74ACT251 is identical in pinout to the LS/ALS251,
HC/HCT251. The IN74ACT251 may be used as a level converter
for interfacing TTL or NMOS outputs to High Speed CMOS inputs.
The device selects one of the eight binary Data Inputs, as
determined by the Address Inputs. The Output Enable pin must be
at a low level for the selected data to appear at the outputs. If
Output Enable is high, the Y and the Y outputs are in the high-
impedance state. This 3-State feature allows the IN74ACT251 to
be used in bus-oriented systems.
• TTL/NMOS Compatible Input Levels
• Outputs Directly Interface to CMOS, NMOS, and TTL
ORDERING INFORMATION
• Operating Voltage Range: 4.5 to 5.5 V
• Low Input Current: 1.0 µA; 0.1 µA @ 25°C
• Outputs Source/Sink 24 mA
IN74ACT251N Plastic
IN74ACT251D SOIC
TA = -40° to 85° C for all
packages
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
Inputs
A2 A1 A0 Output
Enable
Outputs
Y
X
L
X
L
X
L
H
L
Z
Z
D0
D0
D1
D2
D3
D4
D5
D6
D7
L
L
L
H
H
H
H
L
H
H
L
L
H
H
H
L
H
L
H
L
L
L
L
L
L
L
L
D1
D2
D3
D4
D5
D6
D7
PIN 16 =VCC
PIN 8 = GND
H
D0,D1...D7=the level of the
respective D input
Z = high-impedance state
X = don’t care
1
INTEGRAL [ INTEGRAL CORP. ]
