FM803MS3X

Supervisors Overview

The FM803MS3X is a 3-pin CMOS voltage supervisor circuit manufactured by Fairchild Semiconductor, now part of onsemi. It monitors a single power supply rail with a fixed threshold voltage of +4.38V. The device features an active-low, open-drain reset output and operates within a supply voltage range of 1.1V to 5.5V. It provides a typical reset delay time of 560ms and draws a low operating current of 6µA. Designed for surface-mount installation, it is housed in a compact SOT-23 package (PDSO3) suitable for space-constrained applications.

Supervisors Feature Summary

• Provides reliable system reset generation when monitored voltage drops below or exceeds specified thresholds
• Features low quiescent current consumption to extend battery life in portable devices
• Includes internal reset delay timer to ensure stable power-up sequencing

Supervisors Applications

• Microprocessor and microcontroller power supply monitoring
• Battery-powered consumer electronics
• Industrial control systems requiring voltage supervision

Supervisors Procurement Notes

Verify the manufacturer source, as Fairchild Semiconductor was acquired by onsemi. Confirm that the specific suffix 'MS3X' corresponds to the correct tape-and-reel packaging and RoHS compliance status required for your assembly process. Cross-reference the exact threshold voltage and package marking with the official datasheet to avoid substitution errors with similar variants like FM803RS3X.

Supervisors Selection Notes

Select this component when a fixed 4.38V supervision threshold is required for a single-rail system. Ensure the application voltage stays within the 1.1V to 5.5V operational range. Consider the SOT-23-3 package constraints for PCB layout. Verify that the open-drain output interface is compatible with the downstream logic levels of the monitored processor or controller.

Supervisors Part Context

The FM803 series belongs to a family of 3-pin UC Supervisor Circuits originally developed by Fairchild Semiconductor. These devices are designed for simple, cost-effective voltage monitoring in embedded systems. Following the acquisition of Fairchild by onsemi, these parts continue to be supported under the onsemi portfolio, maintaining compatibility with legacy designs while offering updated manufacturing standards.

Supervisors Replacement Considerations

Check for direct pin-compatible alternatives such as the FM803RS3X from onsemi, ensuring threshold voltage matches. Other generic supervisors may require level-shifting if their output types differ from the active-low open-drain configuration.