LM431SCIMFX

Voltage Reference Overview

The LM431SCIMFX is a three-terminal adjustable shunt regulator manufactured by onsemi. It provides thermal stability over the operating temperature range of -40°C to +85°C. The output voltage is programmable between approximately 2.5 V and 36 V using two external resistors. Key electrical characteristics include a reference input voltage tolerance of ±0.5%, a typical dynamic output impedance of 0.2 Ω, and a sink current capability ranging from 1.0 mA to 100 mA. The device features an equivalent full-range temperature coefficient of 50 ppm/°C (typical) and operates with low output noise.

Voltage Reference Feature Summary

• Programmable output voltage settable between VREF and 36 V via external resistors
• Temperature compensated for operation across the full rated operating temperature range
• Active output circuitry providing sharp turn-on characteristics
• Low dynamic output impedance ensuring stable regulation

Voltage Reference Applications

• Shunt regulator circuits
• Output control for three-terminal fixed regulators
• High current shunt regulator designs
• Current limit or current source applications
• Constant-current sink implementations

Voltage Reference Procurement Notes

Verify component authenticity through authorized distribution channels. Confirm package marking matches the SOT-23FL outline. Ensure compliance with RoHS standards as the device is lead-free and halogen-free. Validate that the specific suffix corresponds to the required temperature grade and accuracy class before integration.

Voltage Reference Selection Notes

Select this variant when precise 0.5% initial accuracy is required alongside extended industrial temperature coverage. The SOT-23FL package offers a compact surface-mount solution suitable for space-constrained designs. Consider the minimum cathode current requirement for regulation when designing bias networks for low-power applications.

Voltage Reference Part Context

This component belongs to the LM431SA/SB/SC family of programmable shunt regulators. The SC suffix denotes a tighter initial accuracy tolerance compared to SA or SB variants. The IMFX suffix indicates the specific industrial temperature range and SOT-23FL packaging configuration provided by onsemi.

Voltage Reference Replacement Considerations

LM431SCI

Voltage Reference FAQ

What is the minimum cathode current required for regulation?

The minimum cathode current for regulation is typically 1.0 mA at the reference voltage.

How is the output voltage determined?

The output voltage is set to any value between VREF (approximately 2.5 V) and 36 V using two external resistors.