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74AC157 • 74ACT157 Quad 2-Input Multiplexer
November 1988
Revised November 1999
74AC157 • 74ACT157
Quad 2-Input Multiplexer
General Description
The AC/ACT157 is a high-speed quad 2-input multiplexer.
Four bits of data from two sources can be selected using
the common Select and Enable inputs. The four outputs
present the selected data in the true (noninverted) form.
The AC/ACT157 can also be used as a function generator.
Features
s
I
CC
and I
OZ
reduced by 50%
s
Outputs source/sink 24 mA
s
ACT157 has TTL-compatible inputs
Ordering Code:
Order Number
74AC157SC
74AC157SJ
74AC157MTC
74AC157PC
74ACT157SC
74ACT157SJ
74ACT157MTC
74ACT157PC
Package Number
M16A
M16D
MTC16
N16E
M16A
M16D
MTC16
N16E
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150” Narrow Body
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16 -Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm 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 Body
16-Lead Small Outline Package (SOP), EIAJ TYPE II, 5.3mm Wide
16 -Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300” Wide
Device also available in Tape and Reel. Specify by appending suffix letter “X” to the ordering code.
Logic Symbols
Connection Diagram
IEEE/IEC
Pin Descriptions
Pin Names
I
0a
–I
0d
I
1a
–I
1d
E
S
Z
a
–Z
d
Description
Source 0 Data Inputs
Source 1 Data Inputs
Enable Input
Select Input
Outputs
FACT is a trademark of Fairchild Semiconductor Corporation.
© 1999 Fairchild Semiconductor Corporation
DS009929
www.fairchildsemi.com
74AC157 • 74ACT157
Functional Description
The AC/ACT157 is a quad 2-input multiplexer. It selects
four bits of data from two sources under the control of a
common Select input (S). The Enable input (E) is active-
LOW. When E is HIGH, all of the outputs (Z) are forced
LOW regardless of all other inputs. The AC/ACT157 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. The logic equations for the
outputs are shown below:
Z
a
=
E • (I
1a
• S
+
I
0a
• S)
Z
b
=
E • (I
1b
• S
+
I
0b
• S)
Z
c
=
E • (I
1c
• S
+
I
0c
• S)
Z
d
=
E • (I
1d
• S
+
I
0d
• S)
A common use of the AC/ACT157 is the moving of data
from two groups of registers to four common output bus-
ses. 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/ACT157 can gener-
ate any four of the sixteen different functions of two vari-
ables with one variable common. This is useful for
implementing gating functions.
Truth Table
Inputs
E
H
L
L
L
L
S
X
H
H
L
L
I
0
X
X
X
L
H
I
1
X
L
H
X
X
Outputs
Z
L
L
H
L
H
H
=
HIGH Voltage Level
L
=
LOW Voltage Level
X
=
Immaterial
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
74AC157 • 74ACT157
Absolute Maximum Ratings
(Note 1)
Supply Voltage (V
CC
)
DC Input Diode Current (I
IK
)
V
I
= −0.5V
V
I
=
V
CC
+
0.5V
DC Input Voltage (V
I
)
DC Output Diode Current (I
OK
)
V
O
= −0.5V
V
O
=
V
CC
+
0.5V
DC Output Voltage (V
O
)
DC Output Source
or Sink Current (I
O
)
DC V
CC
or Ground Current
per Output Pin (I
CC
or I
GND
)
Storage Temperature (T
STG
)
Junction Temperature (T
J
)
PDIP
140°C
±50
mA
−65°C
to
+150°C
±50
mA
−20
mA
+20
mA
−0.5V
to V
CC
+
0.5V
−20
mA
+20
mA
−0.5V
to V
CC
+
0.5V
−0.5V
to
+7.0V
Recommended Operating
Conditions
Supply Voltage (V
CC
)
AC
ACT
Input Voltage (V
I
)
Output Voltage (V
O
)
Operating Temperature (T
A
)
Minimum Input Edge Rate (∆V/∆t)
AC Devices
V
IN
from 30% to 70% of V
CC
V
CC
@ 3.3V, 4.5V, 5.5V
Minimum Input Edge Rate (∆V/∆t)
ACT Devices
V
IN
from 0.8V to 2.0V
V
CC
@ 4.5V, 5.5V
125 mV/ns
Note 1:
Absolute maximum ratings are those values beyond which damage
to the device may occur. The databook specifications should be met, with-
out exception, to ensure that the system design is reliable over its power
supply, temperature, and output/input loading variables. Fairchild does not
recommend operation of FACT circuits outside databook specifications.
2.0V to 6.0V
4.5V to 5.5V
0V to V
CC
0V to V
CC
−40°C
to
+85°C
125 mV/ns
DC Electrical Characteristics for AC
Symbol
V
IH
Parameter
Minimum HIGH Level
Input Voltage
V
IL
Maximum LOW Level
Input Voltage
V
OH
Minimum HIGH Level
Output Voltage
V
CC
(V)
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
3.0
4.5
5.5
V
OL
Maximum LOW Level
Output Voltage
3.0
4.5
5.5
3.0
4.5
5.5
I
IN
(Note 4)
I
OLD
I
OHD
I
CC
(Note 4)
Maximum Input
Leakage Current
Minimum Dynamic
Output Current (Note 3)
Maximum Quiescent
Supply Current
5.5
5.5
5.5
5.5
4.0
0.002
0.001
0.001
T
A
= +25°C
Typ
1.5
2.25
2.75
1.5
2.25
2.75
2.99
4.49
5.49
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
2.56
3.86
4.86
0.1
0.1
0.1
0.36
0.36
0.36
±0.1
T
A
= −40°C
to
+85°C
Guaranteed Limits
2.1
3.15
3.85
0.9
1.35
1.65
2.9
4.4
5.4
V
IN
=
V
IL
or V
IH
2.46
3.76
4.76
0.1
0.1
0.1
V
IN
=
V
IL
or V
IH
0.44
0.44
0.44
±1.0
75
−75
40.0
µA
mA
mA
µA
V
I
OL
=
12 mA
I
OL
=
24 mA
I
OL
=
24 mA (Note 2)
V
I
=
V
CC
, GND
V
OLD
=
1.65V Max
V
OHD
=
3.85V Min
V
IN
=
V
CC
or GND
V
I
OUT
=
50
µA
V
I
OH
= −12
mA
I
OH
= −24
mA
I
OH
= −24
mA (Note 2)
V
I
OUT
= −50 µA
V
V
OUT
=
0.1V
or V
CC
−
0.1V
V
Units
Conditions
V
OUT
=
0.1V
or V
CC
−
0.1V
Note 2:
All outputs loaded; thresholds on input associated with output under test.
Note 3:
Maximum test duration 2.0 ms, one output loaded at a time.
Note 4:
I
IN
and I
CC
@ 3.0V are guaranteed to be less than or equal to the respective limit @ 5.5V V
CC
.
3
www.fairchildsemi.com
74AC157 • 74ACT157
DC Characteristics for ACT
Symbol
V
IH
V
IL
V
OH
Parameter
Minimum HIGH Level
Input Voltage
Maximum LOW Level
Input Voltage
Minimum HIGH Level
Output Voltage
V
CC
(V)
4.5
5.5
4.5
5.5
4.5
5.5
4.5
5.5
V
OL
Maximum LOW Level
Output Voltage
4.5
5.5
4.5
5.5
I
IN
I
CCT
I
OLD
I
OHD
I
CC
Maximum Input
Leakage Current
Maximum
I
CC
/Input
Minimum Dynamic
Output Current (Note 6)
Maximum Quiescent
Supply Current
5.5
5.5
5.5
5.5
5.5
4.0
0.6
0.001
0.001
T
A
= +25°C
Typ
1.5
1.5
1.5
1.5
4.49
5.49
2.0
2.0
0.8
0.8
4.4
5.4
3.86
4.86
0.1
0.1
0.36
0.36
±0.1
T
A
= −40°C
to
+85°C
Guaranteed Limits
2.0
2.0
0.8
0.8
4.4
5.4
3.76
4.76
0.1
0.1
0.44
0.44
±1.0
1.5
75
−75
40.0
µA
mA
mA
mA
µA
V
Units
V
V
V
Conditions
V
OUT
=
0.1V
or V
CC
−
0.1V
V
OUT
=
0.1V
or V
CC
−
0.1V
I
OUT
= −50 µA
V
IN
=
V
IL
or V
IH
V
I
OH
= −24
mA
I
OH
= −24
mA (Note 5)
I
OUT
=
50
µA
V
IN
=
V
IL
or V
IH
V
I
OL
=
24 mA
I
OL
=
24 mA (Note 5)
V
I
=
V
CC
, GND
V
I
=
V
CC
−
2.1V
V
OLD
=
1.65V Max
V
OHD
=
3.85V Min
V
IN
=
V
CC
or GND
Note 5:
All outputs loaded; thresholds on input associated with output under test.
Note 6:
Maximum test duration 2.0 ms, one output loaded at a time.
AC Electrical Characteristics for AC
V
CC
Symbol
Parameter
(V)
(Note 7)
t
PLH
t
PHL
t
PLH
t
PHL
t
PLH
t
PHL
Propagation Delay
S to Z
n
Propagation Delay
S to Z
n
Propagation Delay
E to Z
n
Propagation Delay
E to Z
n
Propagation Delay
I
n
to Z
n
Propagation Delay
I
n
to Z
n
Note 7:
Voltage Range 3.3 is 3.3V
±
0.3V
Voltage Range 5.0 is 5.0V
±
0.5V
T
A
= +25°C
C
L
=
50 pF
Min
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
Typ
7.0
5.5
6.5
5.0
7.0
5.5
6.5
5.5
5.0
4.0
5.0
4.0
Max
11.5
9.0
11.0
8.5
11.5
9.0
11.0
9.0
8.5
6.5
8.0
6.5
T
A
= −40°C
to
+85°C
C
L
=
50 pF
Min
1.5
1.5
1.5
1.0
1.5
1.5
1.5
1.0
1.0
1.0
1.0
1.0
Max
13.0
10.0
12.0
9.5
13.0
10.0
12.0
9.5
9.0
7.0
9.0
7.0
ns
ns
ns
Units
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
3.3
5.0
ns
ns
ns
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