FST3244 Octal Bus Switch
June 1997
Revised December 1999
FST3244
Octal Bus Switch
General Description
The Fairchild Switch FST3244 provides 8-bits of high-
speed CMOS TTL-compatible bus switching in a standard
鈥?44 pin-out. The low on resistance of the switch allows
inputs to be connected to outputs without adding propaga-
tion delay or generating additional ground bounce noise.
The device is organized as two 4-bit switches with separate
OE inputs. When OE is LOW, the switch is ON and Port A
is connected to Port B. 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
FST3244WM
FST3244QSC
FST3244MTC
Package Number
M20B
MQA20
MTC20
Package Description
20-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-013, 0.300 Wide
20-Lead Quarter Size Outline Package (QSOP), JEDEC MO-137, 0.150 Wide
20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 4.4mm Wide
Devices also available in Tape and Reel. Specify by appending the suffix letter 鈥淴鈥?to the ordering code.
Logic Diagram
Connection Diagram
Truth Table
Pin Descriptions
Pin Name
OE
1
, OE
2
1A, 2A
1B, 2B
Description
Bus Switch Enable
Bus A
Bus B
OE
1
L
L
H
H
Inputs
OE
2
L
H
L
H
Inputs/Outputs
1A, 1B
1A
=
1B
1A
=
1B
Z
Z
2A, 2B
2A
=
2B
Z
2A
=
2B
Z
漏 1999 Fairchild Semiconductor Corporation
DS500021
www.fairchildsemi.com
1
2
3
4
5
