Integrated Device Technology, Inc.
DESCRIPTION:
The FCT157T, FCT257T/FCT2257T are high-speed quad
2-input multiplexers built using an advanced dual metal CMOS
technology. Four bits of data from two sources can be
selected using the common select input. The four buffered
outputs present the selected data in the true (non-inverting)
form.
The FCT157T has a common, active-LOW, enable input.
When the enable input is not active, all four outputs are held
LOW. A common application of ‘FCT157T is to move data
from two different groups of registers to a common bus.
Another application is as a function generator. The ‘FCT157T
can generate any four of the 16 different functions of two
variables with one variable common.
The FCT257T/FCT2257T have a common Output Enable
( ) input. When is HIGH, all outputs are switched to a
high-impedance state allowing the outputs to interface directly
with bus-oriented systems.
The FCT2257T has balanced output drive with current
limiting resistors. This offers low ground bounce, minimal
undershoot and controlled output fall times-reducing the need
for external series terminating resistors. FCT2xxxT parts are
plug-in replacements for FCTxxxT parts.
FAST CMOS
QUAD 2-INPUT
MULTIPLEXER
IDT54/74FCT157T/AT/CT/DT
IDT54/74FCT257T/AT/CT/DT
IDT54/74FCT2257T/AT/CT
MILITARY AND COMMERCIAL TEMPERATURE RANGES JUNE 1996
1
1996 Integrated Device Technology, Inc. 6.6 2537/6
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
FEATURES:
• Common features:
– Low input and output leakage ≤1µA (max.)
– CMOS power levels
– True TTL input and output compatibility
– VOH = 3.3V (typ.)
– VOL = 0.3V (typ.)
– Meets or exceeds JEDEC standard 18 specifications
– Product available in Radiation Tolerant and Radiation
Enhanced versions
– Military product compliant to MIL-STD-883, Class B
and DESC listed (dual marked)
– Available in DIP, SOIC, SSOP, QSOP, CERPACK
and LCC packages
• Features for FCT157T/257T:
– Std., A, C and D speed grades
– High drive outputs (-15mA IOH, 48mA IOL)
• Features for FCT2257T:
– Std., A, and C speed grades
– Resistor outputs (-15mA I
OH, 12mA IOL Com.)
(-12mA IOH, 12mA IOL Mil.)
– Reduced system switching noise
E
157 Only
3 other multiplexers
OE257 Only
Z
A
Z B–Z D
S
I
1B
–I
1D
I
0B
–I
0D
I
1A
I
0A
2537 drw 01
2537 drw 02
2537 drw 03
FUNCTIONAL BLOCK DIAGRAM
PIN CONFIGURATIONS
LCC
TOP VIEW
4
5
6
7
8
L20-2
18
17
16
15
14
9
10 11 12 13
32
1
20 19
INDEX
GND
NC
Vcc
E or OE*
NC
NC NC
S
I
0A
I
1A
ZA
I0B
I1B
ZB
Z
D
I
1D
I0C
I
1C
ZC
I
0D
DIP/SOIC/QSOP/CERPACK
TOP VIEW
5
6
7
8
S
I
0A
1
2
3
4
16
15
14
13
12
11
10
9
Vcc
P16-1,
D16-1,
SO16-1,
SO16-7
&
E16-1
I
1A
Z
A
I
0B
I
1B
GND
Z
E or OE*
I
0C
I
1C
Z
C
I
0D
I
Z
D
B
1D
* for FCT157, for FCT257/FCT2257.
