Fairchild FST3345 8-Bit Bus Switch Data Sheet
Summary
This high-speed 8-bit bus switch (FST3345) provides reliable, low-delay CMOS TTL-compatible signal routing between two ports. Ideal for hardware designers requiring minimal propagation delay and noise reduction in embedded systems. The manual offers comprehensive guidance on electrical specifications, including recommended operating conditions, absolute maximum ratings, detailed pin configurations, and various SMD/SOIC packages to ensure optimal integration of the switch into your circuit design.
Page 1 Text Content
FST3345 — 8-B it B us Sw itch
March 2008
FST3345 — 8-Bit Bus Switch Features Description
4Ω Switch Connection between Two Ports The FST3345 switch provides eight-bits of high-speed CMOS TTL-compatible bus switching. The low on
Minimal Propagation Delay through the Switch
resistance of the switch allows inputs to be connected to outputs without adding propagation delay or
Low ICC
generating additional ground bounce noise.
Zero Bounce in Flow-through Mode
The device is organized as an eight-bit switch with dual
Control Inputs Compatible with TTL Level
output enable inputs (OE and /OE). When /OE is LOW or OE is HIGH, the switch is ON and port A is connected to port B. When /OE is HIGH, and OE is LOW, the switch is OPEN and a high-impedance state exists between the two ports.
Ordering Information
Operating
Part Number Temperature Package Packing
Method
Range
FST3345WMX -40 to +85°C 20-Lead, Small Outline Integrated Circuit (SOIC), JEDEC
MS-013, 0.300-inch Wide Tape and Reel
FST3345QSC -40 to +85°C 20-Lead Quarter Size Outline Package (QSOP), JEDEC
MO-137, 0.150-inch Wide Tube
FST3345QSCX -40 to +85°C 20-Lead Quarter Size Outline Package (QSOP), JEDEC
MO-137, 0.150-inch Wide Tape and Reel
FST3345MTC -40 to +85°C 20-Lead Thin Shrink Small Outline Package (TSSOP),
JEDEC MO-153, 4.4mm Wide Tube
FST3345MTCX -40 to +85°C 20-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC
MO-153, 4.4mm Wide Tape and Reel
All packages are lead free per JEDEC: J-STD-020B standard. The Fairchild switch family derives from and embodies Fairchild’s proven switch technology used for several years in its 74LVX3L384 (FST3384) bus switch product.
Logic Diagram
OE /OE
Figure 1. Logic Diagram
©1997 Fairchild Semiconductor Corporation www.fairchildsemi.com FST3345 • Rev. 1.0.2
Page Summary Contents For Fairchild FST3345 8-Bit Bus Switch Data Sheet
Manual Details
| Brand | Fairchild |
|---|---|
| Pages | 9 |
| File Size | 434.97 KB |
| Published | June 16, 2026 |
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Frequently Asked Questions
How are ports disconnected in the FST3345?
When /OE is HIGH and OE is LOW, the switch is OPEN and high-impedance exists.
What happens to unused control inputs?
Unused control inputs must be held HIGH or LOW; they cannot float.
What operating temperatures does the FST3345 support?
It operates from -40°C to +85°C.
What package options are available for the FST3345?
SOIC, QSOP, and TSSOP packages in tube or tape and reel.
What is the typical switch on resistance?
The on resistance is typically 4Ω when VIN=0V at IIN=64mA.