
Quad 2-Input Multiplexer
CY54/74FCT157T
SCCS014 - May 1994 - Revised February 2000
Data sheet acquired from Cypress Semiconductor Corporation.
Data sheet modified to remove devices not offered.
Copyright
2000, Texas Instruments Incorporated
Features
Function, pinout, and drive compatible with FCT and
F logic
FCT-C speed at 4.3 ns max. (Com’l),
FCT-A speed at 5.0 ns max. (Com’l)
Reduced V
(typically = 3.3V) versions of equivalent
FCT functions
Edge-rate control circuitry for significantly improved
noise characteristics
Power-off disable feature
Matched rise and fall times
Fully compatible with TTL input and output logic levels
ESD > 2000V
Extended commercial range of
40C to +85C
Sink current
64 mA (Com’l),
32 mA (Mil)
Source current
32 mA (Com’l),
12 mA (Mil)
Functional Description
The FCT157T is a quad two-input multiplexer that selects four
bits of data from two sources under the control of a common
data Select input (S). The Enable input (E) is Active LOW.
When (E) is HIGH, all of the outputs (Y) are forced LOW
regardless of all other input conditions.
Moving data from two groups of registers to four common
output buses is a common use of the FCT157T. The state of
the Select input determines the particular register from which
the data comes. It can also be used as a function generator.
The device is useful for implementing highly irregular logic by
generating any four of the sixteen different functions of two
variables with one variable common.
The FCT157T is a logic implementation of a four-pole,
two-position switch where the position of the switch is
determined by the logic levels supplied to the Select input.
The outputs are designed with a power-off disable feature to
allow for live insertion of boards.
LogicBlockDiagram, FCT157T
Pin Configurations
1
2
3
4
5
6
7
8
V
CC
E
GND
Top View
FCT157T
4
8
9
10
11
12
13
7
6 5
1516 17 18
3
2
1
20
19
14
I
I
Y
I1
I0
I0
NC
Y
c
N
N
V
CC
E
GND
Yd
Top View
SOIC/QSOP
I
LCC
NC
16
15
14
13
12
11
10
9
Y
a
I
0b
S
I
1a
I
0a
I
1d
Y
d
I
0d
I
0a
S
I
1a
I
0b
I
1b
I
0c
I
1c
I
0d
I
1d
Y
a
Y
b
Y
c
Y
d
Y
b
I
1b
I
1c
I
0c
Y
c
S
I
0a
Y
b
I
1c
E
FCT157T–1
Y
a
S
I
1a
I
0a
I
1d
I
0d
Y
b
I
1b
I
0b
I
1c
I
0c
Y
c
Y
d
E
FCT157T
FCT157T
Logic Symbol