FST3345QSC

Overview

The FST3345QSC is an 8-bit bus switch manufactured by onsemi, formerly Fairchild Semiconductor. It provides high-speed CMOS TTL-compatible switching between two ports with a typical on-resistance of 4 Ω at VCC = 4.5 V. The device operates within a supply voltage range of 4.0 V to 5.5 V and supports an operating temperature range from -40 °C to +85 °C. It features dual output enable inputs (OE and /OE) for flexible control logic.

Feature Summary

• Provides eight bits of high-speed CMOS bus switching with minimal propagation delay.
• Features low on-resistance to connect inputs to outputs without generating additional ground bounce noise.
• Includes dual output enable inputs (OE and /OE) for configurable connection states.

Applications

• High-speed data bus switching applications
• TTL-compatible digital circuit interfacing
• Portable electronic devices requiring low power consumption

Procurement Notes

Verify the specific suffix 'QSC' against current official documentation, as legacy Fairchild part numbers may have been updated or renamed during the integration into ON Semiconductor's product management systems. Confirm package availability and ordering information directly through authorized channels to ensure compliance with current system requirements.

Selection Notes

Select this component when designing circuits that require bidirectional data transfer between buses with TTL-compatible logic levels. Ensure the application voltage remains within the 4.0 V to 5.5 V range and verify that the required operating temperature falls within the specified industrial grade limits.

Part Context

This component belongs to the FST series of bus switches, originally developed by Fairchild Semiconductor before its acquisition by ON Semiconductor. The FST3345 specifically addresses the need for low-latency signal routing in digital systems where signal integrity and speed are critical parameters.

Replacement Considerations

Check the ON Semiconductor website for updated part numbers, as underscore characters in original Fairchild designations may have been replaced with dashes. Verify functional equivalence if considering alternative manufacturers' parts.

FAQ

How does the FST3345 handle signal propagation delay?

The device offers minimal propagation delay through the switch, contributing no delay other than the RC delay of the typical on-resistance and load capacitance when driven by an ideal voltage source.

What is the function of the OE and /OE pins?

These are dual output enable inputs. When /OE is LOW or OE is HIGH, the switch connects Port A to Port B. When /OE is HIGH and OE is LOW, the switch disconnects the ports, creating a high-impedance state.