74F158 Fairchild Semiconductor, 74F158 Datasheet - Page 2

• Manufacturer Part Number: 74F158
• Description: Quad 2-Input Multiplexer
• Manufacturer: Fairchild Semiconductor

www.fairchildsemi.com
Unit Loading/Fan Out
Truth Table
H
L
X
Z
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.
n
LOW Voltage Level
HIGH Voltage Level
Immaterial
E
(I
1n
S
H
E
L
L
L
L
I
0n
S)
S
X
H
H
L
L
Inputs
I
I
E
S
Z
0a
1a
Pin Names
a
–Z
–I
–I
0d
1d
I
X
H
X
X
L
d
0
I
X
X
X
H
L
1
Source 0 Data Inputs
Source 1 Data Inputs
Enable Input (Active LOW)
Select Input
Inverted Outputs
Outputs
Z
H
H
H
L
L
Description
2
Functional Description
The F158A 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 regard-
less of all other inputs. The F158A is the logic implementa-
tion 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 F158A 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 F158A can generate four functions
of two variables with one variable common. This is useful
for implementing gating functions.
HIGH/LOW
50/33.3
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
U.L.
Output I
20 A/ 0.6 mA
20 A/ 0.6 mA
20 A/ 0.6 mA
20 A/ 0.6 mA
Input I
1 mA/20 mA
IH
OH
/I
/I
IL
OL