74AC157
QUAD 2 CHANNEL MULTIPLEXER
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HIGH SPEED: tPD = 4ns (TYP.) at VCC = 5V
LOW POWER DISSIPATION:
ICC = 4µA(MAX.) at TA=25°C
HIGH NOISE IMMUNITY:
VNIH = V NIL = 28 % VCC (MIN.)
50Ω TRANSMISSION LINE DRIVING
CAPABILITY
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 24mA (MIN)
BALANCED PROPAGATION DELAYS:
tPLH ≅ tPHL
OPERATING VOLTAGE RANGE:
VCC (OPR) = 2V to 6V
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 157
IMPROVED LATCH-UP IMMUNITY
DESCRIPTION
The 74AC157 is an advanced high-speed CMOS
QUAD 2-CHANNEL MULTIPLEXER fabricated
with sub-micron silicon gate and double-layer
metal wiring C2MOS tecnology.
It consists of four 2-input digital multiplexer with
common SELECT and STROBE inputs. It is a
non-inverting multiplexer. When the STROBE
DIP
SOP
TSSOP
ORDER CODES
PACKAGE
TUBE
DIP
SOP
TSSOP
74AC157B
74AC157M
T&R
74AC157MTR
74AC157TTR
input is held high selection of data is inhibit 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 and outputs are equipped with
protection circuits against static discharge, giving
them 2KV ESD immunity and transient excess
voltage.
PIN CONNECTION AND IEC LOGIC SYMBOLS
April 2001
1/10
74AC157
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
SYMBOL
NAME AND FUNCTION
1
SELECT
2, 5, 11, 14
1A to 4A
3, 6, 10, 13
1B to 4B
4, 7, 9, 12
15
8
16
1Y to 4Y
STROBE
GND
VCC
Common Data Select
Inputs
Data Inputs From Source
A
Data Inputs From Source
B
Multiplexer Outputs
Strobe Input
Ground (0V)
Positive Supply Voltage
TRUTH TABLE
INPUTS
STROBE
SELECT
A
B
Y
H
L
L
L
L
X
L
L
H
H
X
L
H
X
X
X
X
X
L
H
L
L
H
L
H
X : Don’t Care
LOGIC DIAGRAM
2/10
OUTPUT
74AC157
ABSOLUTE MAXIMUM RATINGS
Symbol
VCC
Parameter
Supply Voltage
Value
Unit
-0.5 to +7
V
-0.5 to VCC + 0.5
-0.5 to VCC + 0.5
V
DC Input Diode Current
± 20
mA
IOK
DC Output Diode Current
± 20
mA
IO
DC Output Current
± 50
mA
± 200
mA
VI
DC Input Voltage
VO
DC Output Voltage
IIK
ICC or IGND DC VCC or Ground Current
Tstg
Storage Temperature
TL
Lead Temperature (10 sec)
V
-65 to +150
°C
300
°C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these conditions is
not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
Parameter
Supply Voltage
Value
Unit
2 to 6
V
VI
Input Voltage
0 to VCC
V
VO
Output Voltage
0 to VCC
V
Top
Operating Temperature
-55 to 125
°C
8
ns/V
dt/dv
Input Rise and Fall Time VCC = 3.0, 4.5 or 5.5V (note 1)
1) VIN from 30% to 70% of V CC
3/10
74AC157
DC SPECIFICATIONS
Test Condition
Symbol
VIH
VIL
VOH
VOL
II
ICC
IOLD
IOHD
Parameter
High Level Input
Voltage
Low Level Input
Voltage
High Level Output
Voltage
Low Level Output
Voltage
Input Leakage
Current
Quiescent Supply
Current
Dynamic Output
Current (note 1, 2)
TA = 25°C
VCC
(V)
3.0
4.5
5.5
3.0
4.5
5.5
Value
VO = 0.1 V or
VCC-0.1V
Min.
Typ.
2.1
3.15
3.85
1.5
2.25
2.75
1.5
2.25
2.75
VO = 0.1 V or
VCC-0.1V
Max.
-55 to 125°C
Min.
Min.
Max.
2.1
3.15
3.85
0.9
1.35
1.65
0.9
1.35
1.65
V
0.9
1.35
1.65
IO=-50 µA
2.9
2.99
2.9
2.9
4.5
IO=-50 µA
4.4
4.49
4.4
4.4
5.49
5.5
IO=-50 µA
5.4
5.4
5.4
3.0
IO=-12 mA
2.56
2.46
2.46
4.5
IO=-24 mA
3.86
3.76
3.76
4.86
Unit
Max.
2.1
3.15
3.85
3.0
V
V
5.5
IO=-24 mA
3.0
IO=50 µA
0.002
0.1
0.1
0.1
4.5
IO=50 µA
0.001
0.1
0.1
0.1
5.5
IO=50 µA
0.001
0.1
0.1
0.1
3.0
IO=12 mA
0.36
0.44
0.44
4.5
IO=24 mA
0.36
0.44
0.44
5.5
IO=24 mA
0.36
0.44
0.44
5.5
VI = VCC or GND
± 0.1
±1
±1
µA
5.5
VI = VCC or GND
4
40
80
µA
VOLD = 1.65 V max
75
75
mA
VOHD = 3.85 V min
-75
-75
mA
5.5
4.76
1) Maximum test duration 2ms, one output loaded at time
2) Incident wave switching is guaranteed on trasmission lines with impedances as low as 50Ω
4/10
-40 to 85°C
4.76
V
74AC157
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = tf = 3ns)
Test Condition
Symbol
Parameter
tPLH tPHL Propagation Delay
Time
SELECT to Y
tPLH tPHL Propagation Delay
Time
STROBE to Y
tPLH tPHL Propagation Delay
Time
A, B to Y
Value
TA = 25°C
VCC
(V)
-40 to 85°C
-55 to 125°C
Min.
Typ.
Max.
Min.
Max.
Min.
Max.
(*)
1.5
6.5
11.0
1.5
12.0
1.5
12.0
5.0(**)
1.5
5.0
8.5
1.5
9.5
1.5
9.5
3.3(*)
1.5
6.5
11.0
1.5
12.0
1.5
12.0
(**)
5.0
1.5
5.5
9.0
1.5
10.0
1.5
10.0
3.3(*)
1.5
5.0
8.0
1.5
9.0
1.5
9.0
5.0(**)
1.5
4.0
6.5
1.5
7.0
1.5
7.0
3.3
Unit
ns
ns
ns
(*) Voltage range is 3.3V ± 0.3V
(**) Voltage range is 5.0V ± 0.5V
CAPACITIVE CHARACTERISTICS
Test Condition
Symbol
Parameter
TA = 25°C
VCC
(V)
CIN
Input Capacitance
5.0
CPD
Power Dissipation
Capacitance
(note 1)
5.0
Value
Min.
fIN = 10MHz
Typ.
Max.
-40 to 85°C
-55 to 125°C
Min.
Min.
Max.
Unit
Max.
5
pF
33
pF
1) CPD 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. ICC(opr) = CPD x VCC x f IN + ICC/n (per circuit)
TEST CIRCUIT
CL = 50pF or equivalent (includes jig and probe capacitance)
RL = R1 = 500Ω or equivalent
RT = ZOUT of pulse generator (typically 50Ω)
5/10
74AC157
WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING CONDITIONS (f=1MHz; 50% duty cycle)
WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING CONDITIONS (f=1MHz; 50% duty
cycle)
6/10
74AC157
Plastic DIP-16 (0.25) MECHANICAL DATA
mm
DIM.
MIN.
a1
0.51
B
0.77
TYP.
inch
MAX.
MIN.
TYP.
MAX.
0.020
1.65
0.030
0.065
b
0.5
0.020
b1
0.25
0.010
D
20
0.787
E
8.5
0.335
e
2.54
0.100
e3
17.78
0.700
F
7.1
0.280
I
5.1
0.201
L
Z
3.3
0.130
1.27
0.050
P001C
7/10
74AC157
SO-16 MECHANICAL DATA
mm
DIM.
MIN.
TYP.
A
a1
inch
MAX.
MIN.
TYP.
1.75
0.1
0.068
0.2
a2
MAX.
0.004
0.007
1.65
0.064
b
0.35
0.46
0.013
0.018
b1
0.19
0.25
0.007
0.010
C
0.5
0.019
c1
45 (typ.)
D
9.8
10
0.385
0.393
E
5.8
6.2
0.228
0.244
e
1.27
0.050
e3
8.89
0.350
F
3.8
4.0
0.149
0.157
G
4.6
5.3
0.181
0.208
L
0.5
1.27
0.019
0.050
M
S
0.62
0.024
8 (max.)
P013H
8/10
74AC157
TSSOP16 MECHANICAL DATA
mm
DIM.
MIN.
inch
TYP.
A
MAX.
MIN.
TYP.
MAX.
1.1
0.433
A1
0.05
0.10
0.15
0.002
0.004
0.006
A2
0.85
0.9
0.95
0.335
0.354
0.374
b
0.19
0.30
0.0075
0.0118
c
0.09
0.20
0.0035
0.0079
D
4.9
5
5.1
0.193
0.197
0.201
E
6.25
6.4
6.5
0.246
0.252
0.256
E1
4.3
4.4
4.48
0.169
0.173
0.176
e
0.65 BSC
0.0256 BSC
K
0o
4o
8o
0o
4o
8o
L
0.50
0.60
0.70
0.020
0.024
0.028
A
A2
A1
b
e
K
c
L
E
D
E1
PIN 1 IDENTIFICATION
1
9/10
74AC157
Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from
its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications
mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information
previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or
systems without express written approval of STMicroelectronics.
© The ST logo is a registered trademark of STMicroelectronics
© 2001 STMicroelectronics - Printed in Italy - All Rights Reserved
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10/10
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