74F158A View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
Manufacturer
74F158A Datasheet PDF : 5 Pages
| |||
Unit Loading/Fan Out
Pin Names
Description
I0a–I0d
I1a–I1d
E
S
Za–Zd
Source 0 Data Inputs
Source 1 Data Inputs
Enable Input (Active LOW)
Select Input
Inverted Outputs
U.L.
HIGH/LOW
1.0/1.0
1.0/1.0
1.0/1.0
1.0/1.0
50/33.3
Input IIH/IIL
Output IOH/IOL
20 µA/−0.6 mA
20 µA/−0.6 mA
20 µA/−0.6 mA
20 µA/−0.6 mA
−1 mA/20 mA
Truth Table
Inputs
ES
I0
HX
X
LL
L
LL
H
LH
X
LH
X
H = HIGH Voltage Level
L = LOW Voltage Level
X = Immaterial
Zn = E × (I1nS + I0n S)
Outputs
I1
Z
X
H
X
H
X
L
L
H
H
L
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.
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
|
|
Share Link: 