FST3126QSC

Overview

The FST3126QSC is a high-speed CMOS quadruple bus switch manufactured by Fairchild Semiconductor. It features four independent N-channel field-effect transistors designed for low ON resistance and minimal propagation delay. The device supports active-high enabling and includes undershoot clamp diodes on all switch and control inputs to ensure signal integrity. It operates within an ambient temperature range of -40°C to +85°C and is available in a 16-pin QSOP package.

Feature Summary

• Provides four independent high-speed CMOS switches with low ON resistance for efficient signal routing
• Features active-high enabling logic compatible with standard digital control interfaces
• Integrates undershoot clamp diodes on inputs to protect against voltage excursions below ground

Applications

• Hot-swapping and hot-docking applications requiring safe connection switching
• Voltage translation between 5V and 3.3V logic domains
• Bus isolation for mass storage systems and workstations
• Clock gating and data processing logic replacement

Procurement Notes

Verify the specific suffix 'QSC' against the manufacturer's current datasheet to confirm package type, lead-free status, and RoHS compliance. Ensure the ordering code matches the required 16-pin QSOP configuration. Cross-reference the part number with the official Fairchild or ON Semiconductor catalog to confirm current production status and availability before procurement.

Selection Notes

Select this component when designing systems requiring multiple bidirectional bus switches with low capacitance and fast switching speeds. It is suitable for replacing discrete logic gates in data processing applications. Consider the operating temperature range and input protection features when evaluating suitability for industrial or automotive environments where signal integrity under dynamic conditions is critical.

Part Context

This device belongs to the QuickSwitch family of high-speed bus switches from Fairchild Semiconductor. These components are engineered to provide signal and control switching without adding significant noise, ground bounce, or power consumption to the system. The series is widely used in computing and telecommunications infrastructure for managing data paths efficiently.

Replacement Considerations

The QS3126 is a documented functional substitute within the same product family. Verify pinout compatibility and electrical specifications against the original design requirements before substitution.