STMICROELECTRONICS 74AC157B

74AC157
QUAD 2 CHANNEL MULTIPLEXER
PRELIMINARY DATA
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HIGH SPEED: tPD = 4 ns (TYP.) at VCC = 5V
LOW POWER DISSIPATION:
ICC = 8 µA (MAX.) at TA = 25 oC
HIGH NOISE IMMUNITY:
VNIH = VNIL = 28% VCC (MIN.)
50Ω TRANSMISSION LINE DRIVING
CAPABILITY
SYMMETRICAL OUTPUT IMPEDANCE:
|IOH| = IOL = 24 mA (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 AC157 is an high-speed CMOS QUAD
2-CHANNEL MULTIPLEXER fabricated with
sub-micron silicon gate and double-layer metal
wiring C2MOS technology. It is ideal for low
power applications maintaining high speed
operation similar to equivalent Bipolar Schottky
TTL.
B
M
(Plastic Package)
(Micro Package)
ORDER CODES :
74AC157B
74AC157M
It consists of four 2-input digital multiplexers with
common select and strobe inputs. It is a
non-inverting multiplexer. When the STROBE
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
May 1997
1/9
74AC157
INPUT AND OUTPUT EQUIVALENT CIRCUIT
PIN DESCRIPTION
PIN No
SYMBOL
NAME AND F UNCTIO N
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 Outputs
15
STROBE
Strobe Input
8
GND
Ground (0V)
16
VCC
Positive Supply Voltage
TRUTH TABLE
INPUT
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
X: ”H” or ”L”
LOGIC DIAGRAM
2/9
O UTPUT
ST ROBE
74AC157
ABSOLUTE MAXIMUM RATING
Symbol
VCC
Parameter
Supply Voltage
Value
Unit
-0.5 to +7
V
VI
DC Input Voltage
-0.5 to VCC + 0.5
V
VO
DC Output Voltage
-0.5 to VCC + 0.5
V
IIK
DC Input Diode Current
± 20
mA
IOK
DC Output Diode Current
± 20
mA
IO
DC Output Current
± 50
mA
DC VCC or Ground Current
± 200
mA
ICC or IGND
Tstg
Storage Temperature
TL
Lead Temperature (10 sec)
-65 to +150
o
300
o
C
C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
RECOMMENDED OPERATING CONDITIONS
Symbol
VCC
Parameter
Supply Voltage
Value
Un it
2 to 6
V
V
VI
Input Voltage
0 to VCC
VO
Output Voltage
0 to VCC
Top
dt/dv
Operating Temperature:
Input Rise and Fall Time VCC = 3.0, 4.5 or 5.5 V(note 1)
-40 to +85
8
V
o
C
ns/V
1) VIN from 30% to 70% of VCC
3/9
74AC157
DC SPECIFICATIONS
Symbol
Parameter
Test Con dition s
VIH
High Level Input Voltage
3.0
4.5
VO = 0.1 V or
VCC - 0.1 V
5.5
VIL
Low Level Input Voltage
3.0
4.5
Value
o
High Level Output
Voltage
Typ.
2.1
1.5
2.1
3.15
2.25
3.15
3.85
2.75
VO = 0.1 V or
VCC - 0.1 V
3.0
4.5
Max.
V
3.85
1.5
0.9
0.9
2.25
1.35
1.35
2.75
1.65
2.9
2.99
2.9
IO=-50 µA
4.4
4.49
4.4
5.49
5.4
2.46
4.5
IO=-24 mA
3.86
3.76
5.5
IO=-24 mA
4.86
3.0
IO=50 µA
0.002
0.1
0.1
IO=50 µA
0.001
0.1
0.1
IO=50 µA
0.001
0.1
0.1
4.5
VI(*) =
5.5
VIH or
VIL
V
1.65
IO=-50 µA
2.56
5.4
V
4.76
IO=12 mA
0.36
0.44
4.5
IO=24 mA
0.36
0.44
5.5
IO=24 mA
0.36
0.44
3.0
V
Input Leakage Current
5.5
VI = VCC or GND
±0.1
±1
µA
ICC
Quiescent Supply
Current
5.5
VI = VCC or GND
8
80
µA
IOLD
Dynamic Output Current
(note 1, 2)
5.5
VOLD = 1.65 V max
75
mA
VOHD = 3.85 V min
-75
mA
II
IOHD
1) Maximum test duration 2ms, one output loaded at time
2) Incident wave switching is guaranteed on transmission lines with impedances as low as 50 Ω.
4/9
Min .
IO=-50 µA
3.0
Low Level Output
Voltage
Max.
IO=-12 mA
5.5
VOL
(*)
VI =
VIH or
VIL
-40 to 85 C
Min.
5.5
VOH
Unit
o
T A = 25 C
V CC
(V)
74AC157
AC ELECTRICAL CHARACTERISTICS (CL = 50 pF, RL = 500 Ω, Input tr = t f =3 ns)
Symbol
Parameter
T est Cond ition
3.3(*)
tPLH
tPHL
Propagation Delay Time
SELECT to Y
5.0
tPLH
tPHL
Propagation Delay Time
STROBE to Y
tPLH
tPHL
Propagation Delay Time
A, B to Y
Value
Unit
o
V CC
(V)
o
-40 to 85 C
T A = 25 C
Min. Typ. Max. Min . Max.
1.5
6.5
11.0
1.5
12.0
(**)
1.5
5.0
8.5
1.5
9.5
3.3
5.0(**)
(*)
1.5
1.5
6.5
5.5
11.0
9.0
1.5
1.5
12.0
10.0
3.3(*)
1.5
5.0
8.0
1.5
9.0
(**)
1.5
4.0
6.5
1.5
7.0
5.0
ns
ns
ns
(*) Voltage range is 3.3V ± 0.3V
(**) Voltage range is 5V ± 0.5V
CAPACITIVE CHARACTERISTICS
Symbol
Parameter
Test Con dition s
V CC
(V)
Value
o
T A = 25 C
Min.
Typ.
Max.
Unit
o
-40 to 85 C
Min .
Max.
CIN
Input Capacitance
5.0
4
pF
CPD
Power Dissipation
Capacitance (note 1)
5.0
TBD
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 • VCC • fIN + ICC/n (per circuit)
TEST CIRCUIT
5/9
74AC157
WAVEFORM 1: PROPAGATION DELAYS FOR INVERTING CONDITIONS
WAVEFORM 2: PROPAGATION DELAYS FOR NON-INVERTING CONDITIONS
6/9
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
7/9
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
E
5.8
10
0.385
6.2
0.228
0.393
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
8/9
74AC157
Information furnished is believed to be accurate and reliable. However, SGS-THOMSON Microelectronics assumes no responsability for the
consequences of use of such information nor for any infringement of patents or other rights of third parties which may results from its use. No
license is granted by implication or otherwise under any patent or patent rights of SGS-THOMSON Microelectronics. Specifications mentioned
in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied.
SGS-THOMSON Microelectronics products are not authorized for use as critical components in life support devices or systems without express
written approval of SGS-THOMSON Microelectonics.
 1997 SGS-THOMSON Microelectronics - Printed in Italy - All Rights Reserved
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