FM809MS3X

Supervisors Overview

The FM809MS3X is a voltage supervisory circuit manufactured by Fairchild Semiconductor, designed to monitor power supply integrity. It operates within a supply voltage range of 1.1 V to 5.5 V and features an active low push-pull output. The device includes a fixed reset delay time of 560 ms and detects under-voltage at 3.9 V and over-voltage at 4.18 V. It consumes 10 uA of operating current and functions between -40 C and +105 C in a SOT-23-3 package.

Supervisors Feature Summary

• Provides precise monitoring of single-input voltage levels with defined under-voltage and over-voltage thresholds.
• Delivers a stable active low push-pull signal to trigger system resets or alerts upon detecting power anomalies.
• Incorporates a fixed internal reset delay to ensure stable operation during power transitions.

Supervisors Applications

• Embedded systems requiring reliable power-on reset sequences
• Portable electronics utilizing low-power battery management
• Industrial control units needing voltage supervision in harsh thermal environments

Supervisors Procurement Notes

Verify the specific suffix MS3X against official datasheets to confirm pinout and threshold accuracy. Confirm availability status as distribution channels may list obsolete inventory. Ensure compatibility with existing PCB footprints for SOT-23-3 packages. Validate RoHS compliance documentation for regulatory requirements. Cross-reference manufacturer part numbers to avoid substitution errors with similar series components.

Supervisors Selection Notes

Select this component when a dedicated supervisor with fixed thresholds is required rather than adjustable variants. Consider the 10 uA quiescent current for battery-sensitive designs. Verify that the 560 ms delay aligns with system startup timing requirements. Ensure the operating temperature range meets environmental specifications. Check if manual reset functionality is unnecessary for the target application design.

Supervisors Part Context

The FM809 series comprises 3-pin UC supervisor circuits originally developed by Fairchild Semiconductor. These devices belong to the PMIC category, specifically voltage supervisory circuits. The MS3X suffix typically denotes the SOT-23-3 surface-mount packaging variant within the broader FM809 family of precision reset generators.

Supervisors FAQ

Does the FM809MS3X include a manual reset input?

No, the device does not feature a manual reset input; it relies solely on automatic voltage detection.

What is the specific under-voltage threshold for this model?

The under-voltage threshold is fixed at 3.9 V.