1N4436S

Overview

The Microchip Technology 1N4436S is a precision shunt voltage reference designed for low-voltage Switch Mode Power Supplies (SMPS). It integrates a 0.6V bandgap reference, an error amplifier, and an open-collector output transistor within a single package. The device maintains feedback voltage regulation by sinking current proportional to the error signal at the reference pin. Key electrical specifications include a supply voltage range of 1.7V to 20V, a maximum output saturation voltage of 75mV between the sink terminal and ground, and a typical temperature coefficient of 150ppm/°C. It operates reliably across an industrial temperature range from -40°C to +105°C with a quiescent current of approximately 150µA.

Feature Summary

• Integrates a precision 0.6V voltage reference, amplifier, and open-collector transistor in a compact package
• Features ultra-low saturation voltage enabling series connection with optocouplers for regulation down to 1.8V outputs
• Provides stable closed-loop regulation by sinking current proportional to the error voltage at the REF pin

Applications

• Low voltage Switch Mode Power Supplies (SMPS)
• Power management circuits requiring regulation below standard reference thresholds
• Battery-powered systems utilizing optocoupler-based feedback loops

Procurement Notes

Verify the specific suffix code against official Microchip documentation to confirm exact packaging and tape-and-reel specifications. Ensure the selected variant meets the required industrial temperature range and RoHS compliance standards for your target application environment before finalizing procurement orders.

Selection Notes

Select this component when designing SMPS architectures that require precise regulation at output voltages as low as 1.8V. The low saturation voltage is critical for maintaining accuracy when driving optocouplers directly. Verify that the system's minimum operating voltage exceeds the device's 1.7V requirement and that the thermal design accommodates the specified industrial temperature range.

Part Context

This component belongs to the family of precision analog references used in power conversion applications. Unlike general-purpose Zener diodes, it offers tighter tolerance and lower temperature drift. It serves as a direct functional alternative to legacy TL431-style references but is optimized specifically for lower voltage operation and reduced saturation losses in modern compact power supplies.

Replacement Considerations

Direct substitutes must match the 0.6V reference voltage and open-collector topology. Verify that any replacement device supports the same 1.7V minimum supply voltage and provides comparable saturation voltage characteristics to ensure compatibility with existing optocoupler feedback networks.