FST3383QSC

Overview

The FST3383QSC is a 10-bit low power bus-exchange switch manufactured by onsemi, formerly Fairchild Semiconductor. It provides two sets of high-speed CMOS TTL-compatible bus switches with a typical on-resistance of 5Ω and zero propagation delay. The device operates as a 10-bit bus switch or a 5-bit bus exchanger using the BX signal for nibble swapping. It features ultra-low quiescent supply current (0.2 μA) and zero ground bounce in flow-through mode. Recommended operating conditions specify a supply voltage range of 4.0V to 5.5V and an operating temperature range of -40°C to +85°C.

Feature Summary

• Provides configurable 10-bit bus switching or 5-bit bus exchange functionality via dedicated control signals.
• Features ultra-low on-resistance to minimize signal degradation without adding propagation delay.
• Ensures zero ground bounce noise during operation in flow-through mode.
• Maintains extremely low power consumption with minimal quiescent supply current.

Applications

• Byte swapping of buses in system architectures
• Quad 2-to-1 multiplexer configurations
• Creation of low delay barrel shifters

Procurement Notes

Verify that the component corresponds to the MQA24 package designation when sourcing the FST3383QSC variant. Confirm the manufacturer lineage from Fairchild Semiconductor to onsemi for accurate documentation access. Ensure the application environment remains within the specified -40°C to +85°C temperature range and 4.0V to 5.5V supply voltage limits to maintain electrical characteristics.

Selection Notes

Select this component for designs requiring bidirectional data routing with minimal signal distortion. The integrated bus exchange capability simplifies logic required for byte manipulation compared to discrete multiplexers. Consider the low capacitance and fast enable times for high-frequency applications where timing integrity is critical.

Part Context

This device belongs to the FST series of bus switches derived from proven CMOS technology. It serves as a bridge between different logic families while maintaining signal integrity. The specific QSC suffix denotes the Quarter Size Outline Package (QSOP), distinguishing it from SOIC or TSSOP variants within the same functional family.

Replacement Considerations

Direct replacements include the FST3383WM (SOIC package) and FST3383MTC (TSSOP package). These share identical electrical specifications and pinouts but differ only in physical package dimensions. Verify mechanical clearance before substituting package types.

FAQ

How does the Bus Exchange (BX) signal affect data routing?

When BE is Low and BX is High, the device connects B0-B4 to C0-C4 and D0-D4 to A0-A4, effectively exchanging the nibbles.

What causes the zero propagation delay characteristic?

The switch contributes no propagation delay other than the RC delay of the on-resistance and load capacitance, which is negligible due to the low resistance value.