BU4238F-TR

Overview

The BU4238F-TR is a CMOS voltage detector manufactured by ROHM Semiconductor, designed for monitoring power supply levels in electronic circuits. It features an adjustable delay timer and operates within a supply voltage range of 0.7 V to 7 V. The typical under-voltage detection threshold is 3.8 V with a precision of ±1%. The device provides an open-drain output that goes low during reset conditions. It supports a wide operating temperature range from -40°C to +125°C and consumes minimal current, typically 0.40 μA when active at 4.8 V. The component is housed in a compact SOP-4 package.

Feature Summary

• Adjustable delay timer functionality allows customization of reset timing via external components.
• Open-drain output structure ensures compatibility with various logic families and voltage levels.
• Wide operating voltage range supports diverse power supply architectures.
• High accuracy detection threshold ensures reliable system supervision.

Applications

• Microprocessor and microcontroller power supply supervision
• Battery-operated devices requiring low-power monitoring
• Industrial control systems needing wide temperature operation
• Portable electronics with strict space constraints

Procurement Notes

Verify the specific ordering suffix (e.g., -TR) matches the required tape-and-reel packaging configuration. Confirm the exact detection voltage variant corresponds to the design requirement, as the BU4238 series includes multiple threshold options. Check the latest manufacturer status for availability or last-time-buy notices, as this component may have lifecycle restrictions. Ensure the SOP-4 package dimensions align with the PCB footprint specifications.

Selection Notes

Select this component when an adjustable reset delay is required alongside a fixed 3.8 V detection threshold. Compare the open-drain output drive capability against the load requirements of the downstream circuit. Evaluate the trade-off between the wider operating temperature range (-40°C to 125°C) and cost if industrial-grade performance is not strictly necessary. Consider the SOP-4 package size relative to available board space compared to SSOP alternatives.

Part Context

The BU4238F belongs to the BU42(43)xxF series of voltage detectors from ROHM Semiconductor. This series is characterized by its CMOS technology, low power consumption, and flexible reset timing options. It serves as a supervisory circuit for ensuring stable operation of digital systems by detecting under-voltage conditions and initiating a reset sequence after a user-defined delay period.

Replacement Considerations

The BD5238G-1 is documented as a recommended replacement with the same pinout and similar electrical characteristics, including a 3.8 V detection threshold and adjustable delay. Note that the BD5238G-1 uses an SSOP-5 package, which differs physically from the SOP-4 package of the BU4238F, requiring PCB layout adjustments for substitution.