BU4939F-TR

Supervisors Overview

The BU4939F-TR is a standard CMOS voltage detector IC from ROHM Semiconductor, designed for power supply support applications. It features a fixed detection threshold of 3.9 V with an overvoltage threshold of 3.939 V and high accuracy of ±1%. The device operates within a supply voltage range of 0.7 V to 7 V and consumes ultra-low current, typically 550 nA during operation and 500 nA in standby. It provides a CMOS output type without manual reset or watchdog timer functions. The component is housed in a compact SOP-4 package and supports an extended operating temperature range from -40°C to +125°C.

Supervisors Feature Summary

• Ultra-low current consumption design suitable for battery-powered systems
• High-accuracy voltage detection with ±1% precision
• CMOS output interface for direct logic integration

Supervisors Applications

• Portable electronic devices requiring low power monitoring
• Battery-operated equipment needing under-voltage protection
• General-purpose power supply supervision circuits

Supervisors Procurement Notes

Verify the specific suffix and package configuration against official datasheets before procurement, as variations exist within the series. Confirm availability status, as this part may be subject to lifecycle changes such as Last Time Buy or discontinuation. Ensure compatibility with existing PCB footprints for the SOP-4 package. Cross-reference electrical parameters like threshold voltage and output type with system requirements to avoid functional mismatches.

Supervisors Selection Notes

Select this component when a fixed 3.9 V detection threshold is required with CMOS output characteristics. Consider the SOP-4 package size constraints and the wide operating temperature range for harsh environments. Evaluate the ultra-low current consumption benefits for battery life extension compared to open-drain alternatives if logic level compatibility is needed.

Supervisors Part Context

This component belongs to the BU49xx series of standard CMOS voltage detectors from ROHM Semiconductor. The series offers various detection voltages in 0.1 V increments and includes both Nch open drain and CMOS output options. The BU4939F-TR specifically utilizes the CMOS output variant, distinguishing it from similar parts like the BU48xx series which may feature different output structures.

Supervisors Replacement Considerations

Publicly confirmed substitute part numbers are not available in the provided documentation.