TS4431ILT

Overview

The TS4431ILT is a four-terminal shunt voltage reference manufactured by STMicroelectronics, designed for low-voltage Switch Mode Power Supplies (SMPS). It integrates a 1.224V precision reference, an amplifier, and an open-collector output transistor in a SOT-23-5 package. 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. The device operates with a minimum cathode current of 500 µA and a maximum sink current of 20 mA. It supports an adjustable output voltage up to 10 V and functions within an industrial temperature range of -40°C to +85°C.

Feature Summary

• Integrates a 1.224V internal voltage reference with an amplifier and open collector output transistor
• Features ultra-low saturation voltage between the sink and ground terminals
• Maintains feedback voltage stability through closed-loop current sinking proportional to error signals

Applications

• Low voltage Switch Mode Power Supplies (SMPS)
• Series connection with optocouplers for SMPS regulation
• Precision voltage reference circuits requiring low current consumption

Procurement Notes

Verify the specific suffix 'ILT' corresponds to the SOT-23-5 surface-mount package configuration. Confirm that the required operating temperature range aligns with the industrial specification of -40°C to +85°C. Ensure the design accommodates the 12 V maximum series voltage limit and the 20 mA maximum shunt current capability. Cross-reference the datasheet for pinout compatibility if replacing legacy components like the TL431.

Selection Notes

Select this component when a precise 1.224V reference is needed for low-voltage power supply architectures. The low quiescent current of 250 µA makes it suitable for energy-efficient designs. The open-collector output allows flexible interfacing with optocouplers. Consider the 100 ppm/°C temperature coefficient for thermal stability requirements. The SOT-23-5 package offers a compact footprint for space-constrained PCB layouts.

Part Context

The TS4431 belongs to a family of shunt voltage references similar in operation to the standard TL431. Unlike fixed or higher-voltage variants, this model is specifically optimized for low-voltage SMPS applications. The integration of the reference and driver in a single package simplifies circuit design compared to discrete solutions. It serves as a cost-effective alternative for regulating outputs where high precision and low standby current are critical.

Replacement Considerations

Public confirmed substitute part numbers: None.