TL431ACZ

Overview

The TL431ACZ is a three-terminal adjustable precision shunt regulator manufactured by Fairchild Semiconductor. It provides a guaranteed thermal stability over applicable temperature ranges, with an output voltage programmable to any value between Vref (approximately 2.5 volts) and 36 volts using two external resistors. The device features a typical dynamic output impedance of 0.2 ohms and an active output circuitry that ensures a very sharp turn-on characteristic. It operates within a commercial temperature range of 0°C to 70°C.

Feature Summary

• Programmable output voltage capability up to 36 volts via external resistor divider
• Low dynamic output impedance for stable regulation performance
• Active output circuitry providing fast turn-on response characteristics

Applications

• Board-level DC/DC converters
• Adjustable power supplies
• Switching power supply circuits
• Zener diode replacement applications

Procurement Notes

Verify the specific manufacturer designation as Fairchild Semiconductor was acquired by ON Semiconductor. Confirm the package type matches the TO-92-3 specification found in distributor listings. Ensure the component meets RoHS compliance requirements if mandated by the design specifications. Cross-reference the datasheet revision to confirm pinout compatibility with existing PCB layouts.

Selection Notes

Select this component when a low-cost, high-precision reference voltage is required for shunt regulation applications. The TO-92-3 package is suitable for through-hole mounting on standard printed circuit boards. Consider the operating temperature range limits when designing for environments exceeding 70 degrees Celsius. Verify that the sink current requirements fall within the specified operational capabilities for reliable regulation.

Part Context

This component belongs to the TL431 family of programmable shunt regulators, widely used in power management designs. It serves as a direct functional equivalent to other generic TL431 variants from different manufacturers. The device is commonly utilized in feedback loops for isolated and non-isolated power converters. Its popularity stems from its balance of precision, cost-effectiveness, and widespread availability across multiple packaging options.

Replacement Considerations

Equivalent parts include the KA431 series and generic TL431 components from other vendors such as Texas Instruments or STMicroelectronics. Verify pinout compatibility, particularly regarding the reference, cathode, and anode terminal assignments. Ensure the replacement part supports the same voltage programming range and current sinking capabilities.