CY54FCT157T, CY74FCT157T
QUAD 2-INPUT MULTIPLEXERS
WITH 3-STATE OUTPUTS
SCCS014B – MAY 1994 – REVISED NOVEMBER 2001
D
D
D
D
D
D
D
D
D
D
description
NC – No internal connection
The ’FCT157T devices are quad two-input multiplexers that select four bits of data from two sources under the
control of a common data-select (S) input. The output-enable (E) input 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
devices. The state of S determines the particular register from which the data comes. It also can be used as
a function generator. These devices are useful for implementing highly irregular logic by generating any 4 of
the 16 different functions of 2 variables, with 1 variable common.
The ’FCT157T devices are logic implementations of a four-pole, two-position switch, where the position of the
switch is determined by the logic levels at S.
These devices are fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the
outputs, preventing damaging current backflow through the device when it is powered down.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright
2001, Texas Instruments Incorporated
On products compliant to MIL-PRF-38535, all parameters are tested
unless otherwise noted. On all other products, production
processing does not necessarily include testing of all parameters.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
•
DALLAS, TEXAS 75265
Y
b
GND
NC
Y
c
I
1c
Function, Pinout, and Drive Compatible
With FCT and F Logic
Reduced V
OH
(Typically = 3.3 V) Versions
of Equivalent FCT Functions
Edge-Rate Control Circuitry for
Significantly Improved Noise
Characteristics
I
off
Supports Partial-Power-Down Mode
Operation
Matched Rise and Fall Times
Fully Compatible With TTL Input and
Output Logic Levels
ESD Protection Exceeds JESD 22
– 2000-V Human-Body Model (A114-A)
– 200-V Machine Model (A115-A)
– 1000-V Charged-Device Model (C101)
CY54FCT157T
– 32-mA Output Sink Current
– 12-mA Output Source Current
CY74FCT157T
– 64-mA Output Sink Current
– 32-mA Output Source Current
3-State Outputs
CY74FCT157T . . . Q OR SO PACKAGE
(TOP VIEW)
S
I
0a
I
1a
Y
a
I
0b
I
1b
Y
b
GND
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
CC
E
I
0d
I
1d
Y
d
I
0c
I
1c
Y
c
CY54FCT157T . . . L PACKAGE
(TOP VIEW)
I
0a
S
NC
V
CC
E
I
1a
Y
a
NC
I
0b
I
1b
4
5
6
7
8
3 2 1 20 19
18
17
16
15
14
9 10 11 12 13
I
0d
I
1d
NC
Y
d
I
0c
1
TI [ TEXAS INSTRUMENTS ]
