TECHNICAL DATA
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.
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TTL/NMOS Compatible Input Levels
Outputs Directly Interface to CMOS, NMOS, and TTL
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
ORDERING INFORMATION
IN74ACT251N Plastic
IN74ACT251D SOIC
TA = -40° to 85° C for all packages
PIN ASSIGNMENT
LOGIC DIAGRAM
FUNCTION TABLE
Inputs
Outputs
A2 A1 A0 Output
Enable
Y
Y
X
L
X
L
X
L
H
L
L
L
L
L
L
L
L
Z
Z
D0
D1
D2
D3
D4
D5
D6
D7
D0
D1
D2
D3
D4
D5
D6
D7
L
L
H
L
L
H
H
L
L
H
L
H
H
H
H
L
H
L
PIN 16 =VCC
PIN 8 = GND
H
H
H
D0,D1...D7=the level of the respective D
input
Z = high-impedance state
X = don’t care
Rev. 00
IKSEMICON [ IK SEMICON CO., LTD ]
