FST3257 Quad 2:1 Multiplexer/Demultiplexer Bus Switch
September 1997
Revised December 1999
FST3257
Quad 2:1 Multiplexer/Demultiplexer Bus Switch
General Description
The Fairchild Switch FST3257 is a quad 2:1 high-speed
CMOS TTL-compatible multiplexer/demultiplexer bus
switch. The low on resistance of the switch allows inputs to
be connected to outputs without adding propagation delay
or generating additional ground bounce noise.
When OE is LOW, the select pin connects the A Port to the
selected B Port output. When OE is HIGH, the switch is
OPEN and a high-impedance state exists between the two
ports.
Features
s
4鈩?switch connection between two ports.
s
Minimal propagation delay through the switch.
s
Low l
CC
.
s
Zero bounce in flow-through mode.
s
Control inputs compatible with TTL level.
Ordering Code:
Order Number
FST3257M
FST3257QSC
FST3257MTC
Package Number
M16A
MQA16
MTC16
Package Description
16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
16-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide
16-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Device also available in Tape and Reel. Specify by appending suffix letter 鈥淴鈥?to the ordering code.
Logic Diagram
Connection Diagram
Pin Descriptions
Pin Name
OE
S
A
B
1
鈥揃
2
Description
Bus Switch Enable
Select Input
Bus A
Bus B
Truth Table
S
X
L
H
OE
H
L
L
Function
Disconnect
A
=
B
1
A
=
B
2
漏 1999 Fairchild Semiconductor Corporation
DS500057
www.fairchildsemi.com
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