TS4431AILT

Overview

The TS4431AILT is a four-terminal shunt voltage reference manufactured by STMicroelectronics, designed for low-voltage Switch Mode Power Supplies (SMPS). It integrates a 1.224V internal precision reference with an amplifier and an open-collector output transistor in a single SOT-23-5 package. The device maintains feedback voltage at the REF pin by sinking current proportional to the error signal. Key electrical parameters include an initial accuracy of ±0.5%, a temperature coefficient of 100 ppm/°C, and a maximum input voltage of 12 V. It operates within an industrial temperature range of -40°C to +85°C.

Feature Summary

• Integrates a 1.224V precision voltage reference, amplifier, and open-collector transistor
• Features ultra-low saturation voltage between sink and ground terminals
• Maintains closed-loop regulation via current sinking proportional to REF pin error voltage

Applications

• Low voltage Switch Mode Power Supplies (SMPS)
• Series connection with optocouplers for SMPS architecture regulation

Procurement Notes

Verify the specific suffix 'A' indicates the ±0.5% initial accuracy grade and 'LT' denotes the SOT-23-5 surface-mount package configuration. Confirm that the component meets the required industrial temperature range specifications (-40°C to +85°C) for your application environment. Ensure compatibility with the 12 V maximum input voltage limit during system design validation.

Selection Notes

Select this component when a compact solution for low-voltage SMPS regulation is required. The integrated open-collector output allows direct interfacing with optocouplers, simplifying circuit topology. The 1.224V reference value is suitable for applications requiring precise low-level feedback control without external resistor dividers for basic regulation tasks.

Part Context

The TS4431 belongs to a family of four-terminal shunt references similar in operating mode to standard TL431 devices but optimized for lower voltage applications. Unlike fixed-output references, it utilizes an internal amplifier to regulate the REF pin voltage. The AILT variant specifically provides high precision and small form factor packaging for modern power management designs.

Replacement Considerations

Direct substitutes may include other 1.224V shunt references with compatible pinouts and saturation characteristics. Verify that alternative components support the same 12 V maximum input rating and industrial temperature range. Ensure replacement parts maintain the open-collector output structure for optocoupler integration.