LM431CIM

Voltage Reference Overview

The LM431CIM is a three-terminal adjustable precision Zener shunt regulator manufactured by Texas Instruments, formerly National Semiconductor. It operates within an output voltage range of 2.495 V to 37 V and features an initial accuracy of 0.5%. The device supports a maximum shunt current of 100 mA with a minimum operating current of 1 mA. It exhibits a temperature coefficient of 97 PPM/°C and functions between -40°C and +85°C. Packaged in a surface-mount SOT-23-3 case, it serves as a stable voltage reference for power management applications.

Voltage Reference Feature Summary

• Provides precise adjustable voltage regulation via a two-resistor feedback network
• Ensures guaranteed temperature stability across the full industrial operating range
• Offers low dynamic impedance for improved noise performance in shunt configurations

Voltage Reference Applications

• Precision voltage references in power supply circuits
• Programmable linear and switching regulators
• Over-voltage protection circuits requiring accurate threshold detection

Voltage Reference Procurement Notes

Verify that the component is sourced from authorized distributors to ensure authenticity, as counterfeit versions exist. Confirm the suffix NOPB indicates lead-free and RoHS compliance. Check the specific package marking for SOT-23-3 identification. Ensure the supplier provides valid traceability documentation for quality assurance purposes before finalizing procurement orders.

Voltage Reference Selection Notes

Select this component when a low-cost, high-accuracy shunt regulator is required in a compact surface-mount footprint. The LM431CIM is suitable for designs needing an adjustable reference voltage up to 37 V. Consider the 0.5% initial accuracy and 97 PPM/°C temperature coefficient for thermal stability requirements. Ensure the circuit design accommodates the minimum 1 mA cathode current for proper regulation operation.

Voltage Reference Part Context

The LM431 series originated from National Semiconductor and is now produced by Texas Instruments following their acquisition. The LM431CIM represents the commercial grade version in a small SOT-23-3 package. It is part of a widely adopted family of programmable shunt regulators used globally for voltage referencing and control loop compensation in various electronic systems.

Voltage Reference Replacement Considerations

Direct pin-compatible substitutes include LM431AIMX/NOPB (improved accuracy) or LM431BIMX/NOPB (higher accuracy). Cross-reference with TL431 variants from other manufacturers if sourcing flexibility is needed, ensuring electrical parameters match the original design specifications.