74AC153 Datasheet, PDF (2/9 Pages) Fairchild Semiconductor – Dual 4-Input Multiplexer

Functional Description
Truth Table
The AC/ACT153 is a dual 4-input multiplexer. It can select
two bits of data from up to four sources under the control of
the common Select inputs (S₀, S₁). The two 4-input multi-
plexer circuits have individual active-LOW Enables (E_a, E_b)
which can be used to strobe the outputs independently.
When the Enables (E_a, E_b) are HIGH, the corresponding
outputs Z_a, Z_b) are forced LOW. The AC/ACT153 is the
logic implementation of a 2-pole, 4-position switch, where
the position of the switch is determined by the logic levels
supplied to the Select inputs. The logic equations for the
outputs are shown below.
Select
Inputs
Inputs (a or b)
Output
S₀ S₁
E
I₀
I₁
I₂
I₃
Z
XXHXXXX
L
L
L
L
L
X
X
X
L
L
L
L
H
X
X
X
H
H
L
L
X
LX
X
L
H
L
L
X
HX
X
H
Z_a = E_a • (I_0a • S₁ • S₀ + I_1a • S₁ • S₀ +
I_2a • S₁ • S₀ + I_3a • S₁ • S₀)
Z_b = E_b • (I_0b • S₁ • S₀ + I_1b • S₁ • S₀ +
I_2b • S₁ • S₀ + I_3b • S₁ • S₀)
L
H
L
X
X
L
X
L
L
H
L
X
XH
X
H
H
H
L
X
XX
L
L
H
H
L
X
XX
H
H
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Logic Diagram
Please note that this diagram is provided only for the understanding of logic operations and should not be used to estimate propagation delays.
www.fairchildsemi.com
2