BU4921F-TR

Supervisors Overview

The BU4921F-TR is a standard voltage detector manufactured by ROHM Semiconductor, designed for monitoring power supply integrity. It features a typical under-voltage detection threshold of 2.1 V with a precision of ±1%. The device operates within a reset active voltage range of 0.7 V to 7 V and utilizes a CMOS output type. Key electrical characteristics include a circuit current of 0.40 μA when ON (at VDET=4.8V) and 0.55 μA when OFF. It offers hysteresis defined as VDET x 0.05 and supports an operating temperature range from -40°C to 125°C. The component is housed in an SOP4 package.

Supervisors Feature Summary

• CMOS output interface for digital logic compatibility
• Adjustable hysteresis based on detection voltage ratio
• Single-channel under-voltage monitoring capability

Supervisors Applications

• Portable equipment power management
• Battery-operated device supervision
• General-purpose voltage monitoring circuits

Supervisors Procurement Notes

Verify the obsolete status and Last Time Buy designation before procurement planning. Confirm that the SOP4 package matches the target PCB footprint. Ensure the CMOS output polarity aligns with system requirements. Validate RoHS compliance documentation for regulatory adherence. Check for available substitute components if long-term supply is required.

Supervisors Selection Notes

Select this component for applications requiring low standby current and precise voltage monitoring. The CMOS output simplifies interfacing with microcontrollers. Consider the wide operating temperature range for industrial environments. Verify that the 2.1 V threshold meets the specific system voltage requirements. Evaluate the SOP4 package size constraints against available board space.

Supervisors Part Context

This part belongs to the BU49xx series of standard voltage detectors from ROHM. It is designed for low-power applications where accurate voltage supervision is critical. The series typically includes variants with different detection thresholds and output types. This specific model focuses on cost-effective monitoring with minimal external component requirements.

Supervisors Replacement Considerations

The BD5221G-1 is listed as a recommended replacement with similar specifications. Note that the substitute uses an SSOP5 package, requiring layout adjustments. Verify pinout compatibility and output type differences between CMOS and open drain configurations.