FST3345QSCX

Overview

The FST3345QSCX is an 8-bit bus switch manufactured by onsemi. It provides high-speed CMOS TTL-compatible bus switching with a low on-resistance of 4 Ω between two ports. The device operates within a power supply voltage range of 4.0 V to 5.5 V and supports an input/output voltage range of 0 V to 5.5 V. It features dual output enable inputs (OE and /OE) for flexible control, allowing the connection or disconnection of Port A from Port B. The component is housed in a 20-lead Thin Shrink Small Outline Package (TSSOP).

Feature Summary

• Provides eight bits of high-speed CMOS bus switching.
• Features minimal propagation delay through the switch.
• Includes dual output enable inputs for flexible port control.
• Control inputs are compatible with TTL levels.

Applications

• High-speed data bus switching applications.
• Portable equipment requiring low power consumption.
• Systems utilizing CMOS and TTL logic families.

Procurement Notes

Verify the exact part number against current manufacturer databases, as legacy Fairchild Semiconductor orderable part numbers may have been updated to meet ON Semiconductor system requirements following integration. Confirm package dimensions and tape-and-reel specifications match your manufacturing equipment before finalizing procurement orders.

Selection Notes

Select this component when designing circuits that require bidirectional data transfer between buses with minimal signal degradation. Ensure the operating voltage aligns with the specified 4.0 V to 5.5 V range. Verify that the 20-lead TSSOP package fits the available PCB footprint and that the thermal characteristics support the intended operating temperature range of -40°C to +85°C.

Part Context

This device belongs to the FST series of bus switches, originally developed by Fairchild Semiconductor before its acquisition by ON Semiconductor. The series is designed for high-speed digital applications where low on-resistance and minimal propagation delay are critical for maintaining signal integrity across connected buses.

Replacement Considerations

Check the official ON Semiconductor website for updated ordering information, as legacy Fairchild part numbers containing underscores may have been converted to dashes. Verify pinout compatibility if considering alternative bus switch ICs from other manufacturers.

FAQ

How does the FST3345 handle signal bounce?

The device is designed to exhibit zero bounce in flow-through mode, ensuring clean signal transitions during switching operations.

What is the maximum quiescent supply current?

The typical quiescent supply current (ICC) is 3 µA when VIN is at VCC or GND and IOUT is 0.