SC4431CSK-2TRT

Overview

The SC4431CSK-2TRT is a four-terminal shunt regulator designed for isolated power supplies with output voltages down to 1.5V. It features an open collector output capable of driving optoisolators with as little as 1.5V input voltage. The device utilizes a trimmed bandgap design with initial accuracies to +0.5% and provides 40mA drive capability. It regulates output as low as 50mV while maintaining a wide supply voltage range from 1.5V to 15V. Typical supply current is 110µA, and it operates across the full industrial temperature range in a SOT-23 5-lead package.

Feature Summary

• Four-terminal architecture with separate supply and output pins enables regulation at output voltages as low as 50mV
• Open collector output drives optoisolators with minimal input voltage requirements
• Trimmed bandgap design ensures high initial accuracy
• Capable of sinking current at very low output potentials while maintaining internal functionality

Applications

• Opto driver for very low output voltage (1.5V) isolated power supplies
• Telecom power supplies
• Battery operated applications
• Point of use power supplies

Procurement Notes

Verify the specific suffix '2TRT' against official Semtech documentation to confirm tape and reel packaging specifications. Ensure the component matches the four-terminal SC4431 family rather than standard three-terminal references. Confirm lead-free status and RoHS compliance through the manufacturer's latest environmental declarations before procurement.

Selection Notes

Select this component when standard three-terminal shunt regulators cannot function due to insufficient voltage headroom across an optoisolator. It is suitable for designs requiring regulation below 1.5V where separate supply and output terminals are necessary to maintain device operation. Consider the 40mA drive capability and 110µA quiescent current for power budgeting.

Part Context

The SC4431 series addresses limitations of traditional three-terminal shunt regulators like the SC431L in low-voltage isolated applications. By decoupling the supply and output pins, it allows the reference circuitry to remain active even when the output is near ground potential. This distinguishes it from standard adjustable references that require a minimum dropout voltage between cathode and anode.

Replacement Considerations

Public confirmed substitute part numbers: SC4431CSK-2TR.