DM74AS157 • DM74AS158 Quad 1 of 2 Line Data Selector/Multiplexer
April 1984
Revised March 2000
DM74AS157 • DM74AS158
Quad 1 of 2 Line Data Selector/Multiplexer
General Description
These data selectors/multiplexers contain inverters and
drivers to supply full on-chip data selection to the four out-
put gates. A separate STROBE input is provided. A 4-bit
word is selected from one of two sources and is routed to
the four outputs. The AS157 presents true data whereas
the AS158 presents inverted data to minimize propagation
delay time.
Features
s
Switching specifications at 50 pF
s
Switching specifications guaranteed over full tempera-
ture and V
CC
range
s
Advanced oxide-isolated, ion-implanted Schottky TTL
process
s
Functionally and pin for pin compatible with Schottky,
low power Schottky, and advanced low power Schottky
TTL counterpart
s
Improved AC performance over Schottky, low power
Schottky, and advanced low power Schottky counter-
parts
s
Expand any data input point
s
Multiplex dual data buses
s
General four functions of two variables (one variable is
common)
s
Source programmable counters
Ordering Code:
Order Number
DM74AS157M
DM74AS157SJX
DM74AS157N
DM74AS158M
DM74AS158N
Package Number
M16A
M16D
N16E
M16A
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Connection Diagram
Function Table
Inputs
STROBE Select
H
L
L
L
L
H
=
HIGH Level
L
=
LOW Level
X
=
Don't Care
Output Y
A
X
L
H
X
X
B
X
X
X
L
H
DM74AS157 DM74AS158
L
L
H
L
H
H
H
L
H
L
X
L
L
H
H
© 2000 Fairchild Semiconductor Corporation
DS006290
www.fairchildsemi.com
DM74AS157 • DM74AS158
Absolute Maximum Ratings
(Note 1)
Supply Voltage
Input Voltage
Operating Free Air Temperature Range
Storage Temperature Range
Typical
θ
JA
N Package
75.0
°C/W
7V
7V
0°C to
+70°C
−65°C
to
+150°C
Note 1:
The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.
Recommended Operating Conditions
Symbol
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
Supply Voltage
HIGH Level Input Voltage
LOW Level Input Voltage
HIGH Level Output Current
LOW Level Output Current
Free Air Operating Temperature
0
Parameter
Min
4.5
2
0.8
−2
20
70
Nom
5
Max
5.5
Units
V
V
V
mA
mA
°C
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25°C.
Symbol
V
IK
V
OH
V
OL
I
I
I
IH
I
IL
I
O
(Note 2)
I
CC
Parameter
Input Clamp Voltage
HIGH Level
Output Voltage
LOW Level
Output Voltage
Input Current at Max
Input Voltage
HIGH Level
Input Current
LOW Level
Input Current
Output Drive Current
Supply Current
Conditions
V
CC
=
4.5V, I
I
= −18
mA
V
CC
=
4.5V to 5.5V
I
OH
= −2
mA
V
CC
=
4.5V
I
OL
=
20 mA
V
CC
=
5.5V
V
IH
=
7V
V
CC
=
5.5V
V
IH
=
2.7V
V
CC
=
5.5V
V
IL
=
0.4V
V
CC
=
5.5V, V
O
=
2.25V
V
CC
=
5.5V
DM74AS157
DM74AS158
Select
All Others
Select
All Others
Select
All Others
−30
17.5
15.6
V
CC
−
2
0.35
0.5
0.2
0.1
40
20
−1
−0.5
−112
28
22.5
Min
Typ
Max
−1.2
Units
V
V
V
mA
µA
mA
mA
mA
mA
Note 2:
The output conditions have been chosen to produce a current that closely approximates one half of the true short circuit current, I
OS
.
3
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