54AC158 Datasheet, PDF (2/9 Pages) National Semiconductor (TI) – Quad 2-Input Multiplexer

54AC158, 54ACT158
SNOS090B – JULY 1998 – REVISED APRIL 2013
Connection Diagrams
OBSOLETE
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Figure 3. 16-Pin CDIP or CLGA
See NFE0016A or NAD0016A Package
Figure 4. 20-Pin LCCC
See NAJ0020A Package
Pin Names
Description
I_0a–I_0d
I_1a–I _1d
E
Source 0 Data Inputs
Source 1 Data Inputs
Enable Input
S
Select Input
Z_a–Z_d
Inverted Outputs
FUNCTIONAL DESCRIPTION
The 'AC/'ACT158 quad 2-input multiplexer selects four bits of data from two sources under the control of a
common Select input (S) and presents the data in inverted form at the four outputs. The Enable input (E) is
active-LOW. When E is HIGH, all of the outputs (Z) are forced HIGH regardless of all other inputs. The
'AC/'ACT158 is the logic implementation of a 4-pole, 2-position switch where the position of the switch is
determined by the logic levels supplied to the Select input.
A common use of the 'AC/'ACT158 is the moving of data from two groups of registers to four common output
busses. The particular register from which the data comes is determined by the state of the Select input. A less
obvious use is as a function generator. The 'AC/'ACT158 can generate four functions of two variables with one
variable common. This is useful for implementing gating functions.
Truth Table⁽¹⁾
Inputs
Outputs
E
S
I₀
I₁
Z
H
X
X
X
H
L
L
L
X
H
L
L
H
X
L
L
H
X
L
H
L
H
X
H
L
(1) H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
2
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