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© 2000 Fairchild Semiconductor Corporation DS500319 www.fairchildsemi.com
March 2000
Revised July 2000
FST162861 20-Bit Bus Switch with 25
Ω
Series Resistors in Outputs
FST162861
20-Bit Bus Switch with 25
Ω Series Resistors in Outputs
General Description
The Fairchild Switch FST162861 provides 20-Bits of high-
speed CMOS TTL-compatible bus switching. The low on
resistance of the switch allows inputs to be connected to
outputs without adding propagation delay or generating
additional ground bounce noise.
The device is organized as a 10-bit or 20-Bit bus switch.
When OE
1
is LOW, the switch is ON and Port 1A is con-
nected to Port 1B. When OE
2
is LOW, Port 2A is connected
to Port 2B. When OE
X
is HIGH, a high impedance state
exists between the A and B ports. The FST162861 has an
equivalent 25
Ω series resistors to reduce signal-reflection
noise, eliminating the need for external terminating resis-
tors.
Features
■ 25Ω switch connection between two ports.
■ Minimal propagation delay through the switch.
■ Low l
CC
.
■ Zero bounce in flow-through mode.
■ Control inputs compatible with TTL level.
Ordering Code:
Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.
Logic Diagram
Truth Table
Connection Diagram
Pin Descriptions
Order Number Package Number Package Description
FST162861MTD MTD48 48-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1mm Wide
Inputs Inputs/Outputs
OE
1
OE
2
1A, 1B 2A, 2B
LL1A
= 1B 2A = 2B
LH1A
= 1B Z
HL Z 2A
= 2B
HH Z Z
Pin Name Description
OE
1
, OE
2
Bus Switch Enables
1A, 2A Bus A
1B, 2B Bus B
