2000 Fairchild Semiconductor Corporation
DS006290
www.fairchildsemi.com
April 1984
Revised March 2000
DM74AS157
DM74AS158
Quad 1
of
2
Line
Dat
a
Sel
ect
or/
M
ul
ti
pl
exer
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:
Devices also available in Tape and Reel. Specify by appending the suffix letter "X" to the ordering code.
Connection Diagram
Function Table
H
=
HIGH Level
L
=
LOW Level
X
=
Don't Care
Order Number
Package Number
Package Description
DM74AS157M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74AS157SJX
M16D
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
DM74AS157N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
DM74AS158M
M16A
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
DM74AS158N
N16E
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Inputs
Output Y
STROBE Select
A
B
DM74AS157 DM74AS158
H
X
X
X
L
H
L
L
L
X
L
H
L
L
H
X
H
L
L
H
X
L
L
H
L
H
X
H
H
L
3
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DM74AS157
DM74AS158
Absolute Maximum Ratings
(Note 1)
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
Electrical Characteristics
over recommended operating free air temperature range. All typical values are measured at V
CC
=
5V, T
A
=
25
C.
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
.
Supply Voltage
7V
Input Voltage
7V
Operating Free Air Temperature Range
0
C to
+
70
C
Storage Temperature Range
-
65
C to
+
150
C
Typical
JA
N Package
75.0
C/W
Symbol
Parameter
Min
Nom
Max
Units
V
CC
Supply Voltage
4.5
5
5.5
V
V
IH
HIGH Level Input Voltage
2
V
V
IL
LOW Level Input Voltage
0.8
V
I
OH
HIGH Level Output Current
-
2
mA
I
OL
LOW Level Output Current
20
mA
T
A
Free Air Operating Temperature
0
70
C
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
IK
Input Clamp Voltage
V
CC
=
4.5V, I
I
=
-
18 mA
-
1.2
V
V
OH
HIGH Level
V
CC
=
4.5V to 5.5V
V
CC
-
2
V
Output Voltage
I
OH
=
-
2 mA
V
OL
LOW
Level V
CC
=
4.5V
0.35
0.5
V
Output Voltage
I
OL
=
20 mA
I
I
Input Current at Max
V
CC
=
5.5V
Select
0.2
mA
Input Voltage
V
IH
=
7V
All Others
0.1
I
IH
HIGH Level
V
CC
=
5.5V
Select
40
A
Input Current
V
IH
=
2.7V
All Others
20
I
IL
LOW
Level V
CC
=
5.5V
Select
-
1
mA
Input Current
V
IL
=
0.4V
All Others
-
0.5
I
O
(Note 2)
Output Drive Current
V
CC
=
5.5V, V
O
=
2.25V
-
30
-
112
mA
I
CC
Supply Current
V
CC
=
5.5V
DM74AS157
17.5
28
mA
DM74AS158
15.6
22.5
mA
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4
DM
74AS157
DM
74AS158
DM74AS157 Switching Characteristics
over recommended operating free air temperature range
DM74AS158 Switching Characteristics
over recommended operating free air temperature range
Symbol
Parameter
Conditions
From
To
Min
Max
Units
(Input)
(Output)
t
PLH
Propagation Delay Time,
V
CC
=
4.5V to 5.5V,
Data
Y
1
6
ns
LOW-to-HIGH Level Output
C
L
=
50 pF,
t
PHL
Propagation Delay Time,
R
L
=
500
Data
Y
1
5.5
ns
HIGH-to-LOW Level Output
t
PLH
Propagation Delay Time,
STROBE
Y
2
10.5
ns
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time,
STROBE
Y
2
7.5
ns
HIGH-to-LOW Level Output
t
PLH
Propagation Delay Time,
Select
Y
2
11
ns
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time,
Select
Y
2
10
ns
HIGH-to-LOW Level Output
Symbol
Parameter
Conditions
From
To
Min
Max
Units
(Input)
(Output)
t
PLH
Propagation Delay Time,
V
CC
=
4.5V to 5.5V,
Data
Y
1
5
ns
LOW-to-HIGH Level Output
C
L
=
50 pF,
t
PHL
Propagation Delay Time,
R
L
=
500
Data
Y
1
4.5
ns
HIGH-to-LOW Level Output
t
PLH
Propagation Delay Time,
STROBE
Y
2
6.5
ns
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time,
STROBE
Y
2
10
ns
HIGH-to-LOW Level Output
t
PLH
Propagation Delay Time,
Select
Y
2
9.5
ns
LOW-to-HIGH Level Output
t
PHL
Propagation Delay Time,
Select
Y
2
10.5
ns
HIGH-to-LOW Level Output
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