74AC157
QUAD 2 CHANNEL MULTIPLEXER
PRELIMINARY DATA
May 1997
s
HIGH SPEED: t
PD
= 4 ns (TYP.) at V
CC
= 5V
s
LOW POWER DISSIPATION:
I
CC
= 8
A (MAX.) at T
A
= 25
o
C
s
HIGH NOISE IMMUNITY:
V
NIH
= V
NIL
= 28% V
CC
(MIN.)
s
50
TRANSMISSION LINE DRIVING
CAPABILITY
s
SYMMETRICAL OUTPUT IMPEDANCE:
|I
OH
| = I
OL
= 24 mA (MIN)
s
BALANCED PROPAGATION DELAYS:
t
PLH
t
PHL
s
OPERATING VOLTAGE RANGE:
V
CC
(OPR) = 2V to 6V
s
PIN AND FUNCTION COMPATIBLE WITH
74 SERIES 157
s
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 C
2
MOS technology. It is ideal for low
power
applications
maintaining
high
speed
operation similar to equivalent Bipolar Schottky
TTL.
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
M
(Micro Package)
B
(Plastic Package)
ORDER CODES :
74AC157B
74AC157M
1/9
RECOMMENDED OPERATING CONDITIONS
Symbol
Parameter
Value
Un it
V
CC
Supply Voltage
2 to 6
V
V
I
Input Voltage
0 to V
CC
V
V
O
Output Voltage
0 to V
CC
V
T
op
Operating Temperature:
-40 to +85
o
C
dt/dv
Input Rise and Fall Time V
CC
= 3.0, 4.5 or 5.5 V(note 1)
8
ns/V
1) V
IN
from 30% to 70% of V
CC
ABSOLUTE MAXIMUM RATING
Symbol
Parameter
Val ue
Uni t
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
50
mA
I
CC
or I
GND
DC V
CC
or Ground Current
200
mA
T
stg
Storage Temperature
-65 to +150
o
C
T
L
Lead Temperature (10 sec)
300
o
C
Absolute Maximum Ratings are those values beyond which damage to the device may occur. Functional operation under these condition is not implied.
74AC157
3/9
DC SPECIFICATIONS
Symbol
Parameter
Test Con dition s
Value
Unit
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Mi n.
Typ.
Max.
Min .
Max.
V
IH
High Level Input Voltage
3.0
V
O
= 0.1 V or
V
CC
- 0.1 V
2.1
1.5
2.1
V
4.5
3.15
2.25
3.15
5.5
3.85
2.75
3.85
V
IL
Low Level Input Voltage
3.0
V
O
= 0.1 V or
V
CC
- 0.1 V
1.5
0.9
0.9
V
4.5
2.25
1.35
1.35
5.5
2.75
1.65
1.65
V
OH
High Level Output
Voltage
3.0
V
I
(*)
=
V
IH
or
V
IL
I
O
=-50
A
2.9
2.99
2.9
V
4.5
I
O
=-50
A
4.4
4.49
4.4
5.5
I
O
=-50
A
5.4
5.49
5.4
3.0
I
O
=-12 mA
2.56
2.46
4.5
I
O
=-24 mA
3.86
3.76
5.5
I
O
=-24 mA
4.86
4.76
V
OL
Low Level Output
Voltage
3.0
V
I
(*)
=
V
IH
or
V
IL
I
O
=50
A
0.002
0.1
0.1
V
4.5
I
O
=50
A
0.001
0.1
0.1
5.5
I
O
=50
A
0.001
0.1
0.1
3.0
I
O
=12 mA
0.36
0.44
4.5
I
O
=24 mA
0.36
0.44
5.5
I
O
=24 mA
0.36
0.44
I
I
Input Leakage Current
5.5
V
I
= V
CC
or GND
0.1
1
A
I
CC
Quiescent Supply
Current
5.5
V
I
= V
CC
or GND
8
80
A
I
OLD
Dynamic Output Current
(note 1, 2)
5.5
V
OLD
= 1.65 V max
75
mA
I
OHD
V
OHD
= 3.85 V min
-75
mA
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
.
74AC157
4/9
CAPACITIVE CHARACTERISTICS
Symbol
Parameter
Test Con dition s
Value
Unit
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Mi n.
Typ.
Max.
Min .
Max.
C
IN
Input Capacitance
5.0
4
pF
C
PD
Power Dissipation
Capacitance (note 1)
5.0
TBD
pF
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
V
CC
f
IN
+ I
CC
/n (per circuit)
AC ELECTRICAL CHARACTERISTICS (C
L
= 50 pF, R
L
= 500
, Input t
r
= t
f
=3 ns)
Symbol
Parameter
T est Cond iti on
Value
Unit
V
CC
(V)
T
A
= 25
o
C
-40 to 85
o
C
Mi n.
Typ.
Max.
Min .
Max.
t
PLH
t
PHL
Propagation Delay Time
SELECT to Y
3.3
(*)
1.5
6.5
11.0
1.5
12.0
ns
5.0
(**)
1.5
5.0
8.5
1.5
9.5
t
PLH
t
PHL
Propagation Delay Time
STROBE to Y
3.3
(*)
1.5
6.5
11.0
1.5
12.0
ns
5.0
(**)
1.5
5.5
9.0
1.5
10.0
t
PLH
t
PHL
Propagation Delay Time
A, B to Y
3.3
(*)
1.5
5.0
8.0
1.5
9.0
ns
5.0
(**)
1.5
4.0
6.5
1.5
7.0
(*) Voltage range is 3.3V
0.3V
(**) Voltage range is 5V
0.5V
TEST CIRCUIT
74AC157
5/9
PDF 
ZIP