1/9
September 2001
s
HIGH SPEED:
t
PD
= 16ns (TYP.) at V
CC
= 4.5V
s
LOW POWER DISSIPATION:
I
CC
= 4
A(MAX.) at T
A
=25C
s
COMPATIBLE WITH TTL OUTPUTS :
V
IH
= 2V (MIN.) V
IL
= 0.8V (MAX)
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 4mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 157
DESCRIPTION
The M74HCT157 is an high speed CMOS QUAD
2 CHANNEL MULTIPLEXER fabricated with
silicon gate C
2
MOS technology.
This device consists of four 2-input digital
multiplexer with common select and strobe inputs.
When the STROBE(ST) input is held high,
selection of data is inhibited and all the outputs
become low. The SELECT decoding determines
whether the A or B inputs get routed to their
corresponding Y outputs.
All inputs are equipped with protection circuits
against static discharge and transient excess
voltage.
M74HCT157
QUAD 2 CHANNEL MULTIPLEXER
PIN CONNECTION AND IEC LOGIC SYMBOLS
ORDER CODES
PACKAGE
TUBE
T & R
DIP
M74HCT157B1R
SOP
M74HCT157M1R
M74HCT157RM13TR
TSSOP
M74HCT157TTR
TSSOP
DIP
SOP
M74HCT157
2/9
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
TRUTH TABLE
X : Don't Care
LOGIC DIAGRAM
PIN No
SYMBOL
NAME AND FUNCTION
1
SELECT
Common Data Select
Input
2, 5, 11, 14
1A to 4A
Data Inputs From
Source A
3, 6, 10, 13
1B to 4B
Data Inputs From
Source B
4, 7, 9, 12
1Y to 4Y
Multiplexer Output
15
STROBE
Strobe Inputs
8
GND
Ground (0V)
16
V
CC
Positive Supply Voltage
INPUTS
OUTPUTS
STROBE
SELECT
A
B
Y
H
X
X
X
L
L
L
L
X
L
L
L
H
X
H
L
H
X
L
L
L
H
X
H
H
M74HCT157
3/9
ABSOLUTE MAXIMUM RATINGS
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied
(*) 500mW at 65
C; derate to 300mW by 10mW/
C from 65
C to 85
C
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
-0.5 to +7
V
V
I
DC Input Voltage
-0.5 to V
CC
+ 0.5
V
V
O
DC Output Voltage
-0.5 to V
CC
+ 0.5
V
I
IK
DC Input Diode Current
20
mA
I
OK
DC Output Diode Current
20
mA
I
O
DC Output Current
25
mA
I
CC
or I
GND
DC V
CC
or Ground Current
50
mA
P
D
Power Dissipation
500(*)
mW
T
stg
Storage Temperature
-65 to +150
C
T
L
Lead Temperature (10 sec)
300
C
Symbol
Parameter
Value
Unit
V
CC
Supply Voltage
4.5 to 5.5
V
V
I
Input Voltage
0 to V
CC
V
V
O
Output Voltage
0 to V
CC
V
T
op
Operating Temperature
-55 to 125
C
t
r
, t
f
Input Rise and Fall Time (V
CC
= 4.5 to 5.5V)
0 to 500
ns
M74HCT157
4/9
DC SPECIFICATIONS
* : Applicable only to DIR, G, G input
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, Input t
r
= t
f
= 6ns)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
V
IH
High Level Input
Voltage
4.5
to
5.5
2.0
2.0
2.0
V
V
IL
Low Level Input
Voltage
4.5
to
5.5
0.8
0.8
0.8
V
V
OH
High Level Output
Voltage
4.5
I
O
=-20
A
4.4
4.5
4.4
4.4
V
I
O
=-4.0 mA
4.18
4.31
4.13
4.10
V
OL
Low Level Output
Voltage
4.5
I
O
=20
A
0.0
0.1
0.1
0.1
V
I
O
=4.0 mA
0.17
0.26
0.33
0.40
I
I
Input Leakage
Current
5.5
V
I
= V
CC
or GND
0.1
1
1
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
4
40
80
A
I
CC
Additional Worst
Case Supply
Current
5.5
Per Input pin
V
I
= 0.5V or
V
I
= 2.4V
Other Inputs at
V
CC
or GND
I
O
= 0
2.0
2.9
3.0
mA
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
t
TLH
t
THL
Output Transition
Time
4.5
8
15
19
22
ns
t
PLH
t
PHL
Propagation Delay
Time (A, B - Y)
4.5
16
25
31
38
ns
t
PLH
t
PHL
Propagation Delay
Time (SELECT - Y)
4.5
19
30
38
45
ns
t
PLH
t
PHL
Propagation Delay
Time (STROBE -Y)
4.5
17
27
34
41
ns
M74HCT157
5/9
CAPACITIVE CHARACTERISTICS
1) C
PD
is defined as the value of the IC's internal equivalent capacitance which is calculated from the operating current consumption without
load. (Refer to Test Circuit). Average operating current can be obtained by the following equation. I
CC(opr)
= C
PD
x V
CC
x f
IN
+ I
CC
/4(per chan-
nel)
TEST CIRCUIT
C
L
= 50pF or equivalent (includes jig and probe capacitance)
R
T
= Z
OUT
of pulse generator (typically 50
)
WAVEFORM : PROPAGATION DELAY TIMES (f=1MHz; 50% duty cycle)
Symbol
Parameter
Test Condition
Value
Unit
V
CC
(V)
T
A
= 25C
-40 to 85C
-55 to 125C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
C
IN
Input Capacitance
5.0
5
10
10
10
pF
C
PD
Power Dissipation
Capacitance (note
1)
5.0
50
pF
PDF 
ZIP