FSTU3125MX

Overview

The FSTU3125MX is a high-speed CMOS bus switch manufactured by Fairchild Semiconductor, organized as four independent 1-bit switches. It features an SOIC-14 package and operates within a temperature range of -40°C to 85°C. The device provides undershoot protection down to -2V on both Port A and Port B inputs via integrated Undershoot Hardened Circuitry (UHC). Control inputs are TTL-compatible, and the low on-resistance minimizes propagation delay and ground bounce noise.

Feature Summary

• Undershoot hardened to -2V on A and B Ports
• Minimal propagation delay through the switch
• Low Icc power consumption
• Zero bounce in flow-through mode

Applications

• High-speed data bus switching applications
• Systems requiring extended voltage tolerance below ground
• TTL-compatible logic interface circuits

Procurement Notes

Verify the specific suffix 'MX' against official Fairchild documentation to confirm it denotes tape-and-reel packaging for the SOIC-14 variant. Ensure the component matches the FSTU3125 family specifications regarding the -2V undershoot protection and TTL control compatibility before integration into designs.

Selection Notes

Select this component when circuit requirements demand robust protection against signal undershoot events exceeding standard ground levels. The four-channel configuration supports parallel data paths, while the separate OE inputs allow precise individual control over each switch channel without affecting others.

Part Context

This part belongs to the Fairchild Switch FSTU3125 family, which utilizes proven CMOS technology similar to the FST3384 series. The device is designed to connect inputs to outputs with minimal signal degradation, serving as a reliable solution for managing multiple digital signal lines in compact surface-mount packages.

Replacement Considerations

The FST3125M serves as a related alternative within the same product family. Verify if the replacement requires the specific -2V undershoot protection feature, as standard variants may lack the UHC circuitry present in the FSTU3125 series.