FAST CMOS
QUAD 2-INPUT
MULTIPLEXER
Integrated Device Technology, Inc.
IDT54/74FCT157T/AT/CT/DT
IDT54/74FCT257T/AT/CT/DT
IDT54/74FCT2257T/AT/CT
FEATURES:
• Common features:
– Low input and output leakage
≤1µA
(max.)
– CMOS power levels
– True TTL input and output compatibility
– V
OH
= 3.3V (typ.)
– V
OL
= 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 I
OH
, 48mA I
OL
)
• Features for FCT2257T:
– Std., A, and C speed grades
– Resistor outputs (-15mA I
OH
, 12mA I
OL
Com.)
(-12mA I
OH
, 12mA I
OL
Mil.)
– Reduced system switching noise
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
(
OE
) input. When
OE
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.
FUNCTIONAL BLOCK DIAGRAM
S
PIN CONFIGURATIONS
S
I
0A
I
1A
Z
A
I
0B
I
1B
Z
B
GND
1
2
3
4
5
6
7
8
16
15
157 Only
E
3 other multiplexers
P16-1,
D16-1,
SO16-1,
SO16-7
&
E16-1
14
13
12
11
10
9
I
1B
–I
1D
I
0B
–I
0D
Z
B
–Z
D
Vcc
E or OE*
I
0C
I
1C
Z
C
I
0D
I
1D
Z
D
2537 drw 02
DIP/SOIC/QSOP/CERPACK
TOP VIEW
Z
A
I
0A
S
NC
Vcc
E or OE*
3
2
4
5
6
7
8
I
1A
I
0A
257 Only
OE
INDEX
2537 drw 01
I
1A
Z
A
NC
I
0B
I
1B
L20-2
20 19
18
1
17
16
15
14
10 11 12 13
9
I
0C
I
1C
NC
Z
C
I
0D
LCC
TOP VIEW
The IDT logo is a registered trademark of Integrated Device Technology, Inc.
Z
B
GND
NC
Z
D
I
1D
2537 drw 03
*
E
for FCT157,
OE
for FCT257/FCT2257.
MILITARY AND COMMERCIAL TEMPERATURE RANGES
©1996
Integrated Device Technology, Inc.
JUNE 1996
2537/6
6.6
1
IDT [ INTEGRATED DEVICE TECHNOLOGY ]
