74FST3125QSR

Overview

The onsemi 74FST3125QSR is a quad, high-performance bus switch designed for CMOS and TTL compatibility within a 4.0 V to 5.5 V supply voltage range. It features four independent 1-bit switches with separate Output/Enable (OE) pins, connecting Port A to Port B when OE is low and entering a high-impedance state when OE is high. The device exhibits an extremely low typical on-resistance of 4 Ω and adds nearly zero propagation delay, ensuring minimal signal distortion.

Feature Summary

• Provides four independent 1-bit switches with individual control inputs
• Features enhanced N-channel FETs with no inherent diode to Vcc
• Includes undershoot clamp diodes on all switch and control inputs
• Supports hot-swapping, hot-docking, and voltage translation applications

Applications

• Hot-swapping and hot-docking systems
• Voltage translation between 5V and 3.3V domains
• Capacitance reduction and isolation in mass storage and workstations
• Logic replacement for data processing circuits
• Clock gating and bus isolation

Procurement Notes

Verify the specific package suffix 'QS' corresponds to the QSOP-16 configuration required for your design. Confirm that the ordering number matches the exact tape and reel specifications needed for automated assembly processes. Ensure the component meets RoHS compliance standards if applicable to your manufacturing requirements.

Selection Notes

Select this component for applications requiring low resistance switching without generating ground bounce noise. It serves as a pin-for-pin compatible alternative to QS3125, FST3125, and CBT3125 devices. Consider its suitability for analog switching tasks such as video signals due to its high-speed performance characteristics.

Part Context

This part belongs to the 74FST logic family, characterized by high-speed CMOS technology. It functions as a bus switch rather than a standard buffer or driver. The device is manufactured by onsemi and is available in multiple packages including SOIC-14, TSSOP-14, and QSOP-16.

Replacement Considerations

The datasheet explicitly lists pin-for-pin compatibility with QS3125, FST3125, and CBT3125. These parts can be considered direct substitutes based on functional equivalence and physical footprint matching.