74FST3251QSR

Overview

The onsemi 74FST3251QSR is an 8:1 multiplexer/demultiplexer bus switch manufactured in a QSOP-16 package. It operates within a supply voltage range of 4.0 to 5.5 volts and supports data rates with nearly zero propagation delay. The device features extremely low on-resistance, typically less than 4 ohms at 4.5V, and adds no noise or ground bounce to the system. Control inputs are compatible with both TTL and CMOS logic levels.

Feature Summary

• High-performance 8:1 multiplexer/demultiplexer bus switch
• CMOS and TTL compatible control inputs
• Extremely low on-resistance for minimal signal degradation
• Zero propagation delay and zero ground bounce

Applications

• Logic replacement
• Video, audio, and graphics switching
• Hot-swapping and hot-docking systems
• Voltage translation between 5V and 3.3V domains

Procurement Notes

Verify that the ordering suffix QSR corresponds specifically to the QSOP-16 package type as documented in the official datasheet. Confirm compliance requirements such as lead-free status if applicable to your assembly process. Ensure all unused control inputs are tied to valid high or low logic levels during operation to prevent undefined states.

Selection Notes

Select this component when designing circuits requiring fast, bidirectional data routing with minimal signal distortion. It serves as a function-compatible alternative to legacy 74F, 74FCT, and 74ALS/AS/LS series devices. Consider its low standby current and robust ESD protection characteristics for sensitive digital interfaces.

Part Context

This part belongs to the 74FST (Fast Switching Technology) family from onsemi, designed for high-speed digital applications. It provides enhanced performance over standard logic families by combining low power consumption with very fast switching speeds. The device integrates multiple independent switches into a single compact package.

Replacement Considerations

Functionally pin-compatible replacements include the 74F251, 74FCT251, and 74ALS/AS/LS251 multiplexers. Verify electrical specifications such as on-resistance and propagation delay to ensure they meet your specific circuit requirements before substituting.