BU45K312G-TL

Overview

The BU45K312G-TL is a fixed-delay voltage detector IC from ROHM Semiconductor, designed for monitoring power supply voltages. It features a typical under-voltage detection threshold of 3.1V with ±1% precision. The device provides an open-drain output that activates when the input voltage falls below the detection level, triggering a reset signal after a fixed delay of 200ms. It operates within a supply voltage range of 0.6V to 6V and consumes low current, with typical values of 2.3μA in the ON state and 2.8μA in the OFF state. The component is housed in an SSOP-3 package and supports an operating temperature range from -40°C to +105°C.

Feature Summary

• Integrates a built-in counter timer delay circuit to eliminate the need for external capacitors for delay time setting.
• Provides high accuracy voltage detection with a typical precision of ±1%.
• Features low current consumption suitable for battery-powered applications.
• Utilizes an open-drain output type for flexible interface compatibility.

Applications

• Monitoring microprocessor and microcomputer power supplies.
• Reset circuits for digital logic systems.
• Battery-operated devices requiring voltage supervision.

Procurement Notes

Verify the specific ordering suffix TL against the manufacturer's latest documentation to ensure correct packaging and tape specifications. Confirm that the component status remains acceptable for existing designs, as it may be marked not recommended for new designs. Cross-reference the RoHS compliance status and lead times with authorized distributors prior to procurement.

Selection Notes

Select this component when a fixed 200ms reset delay is required without external timing components. Ensure the 3.1V detection threshold aligns with the system's minimum operating voltage requirements. Consider the SSOP-3 package constraints and the open-drain output drive capability relative to the load connected to the reset line.

Part Context

This part belongs to the BU45/BU46 series of highly accurate, low current consumption voltage detector ICs. These devices are characterized by their integrated delay timers and compact packaging options, targeting space-constrained electronic designs where reliable power supervision is critical.

Replacement Considerations

The BD5231G-1 is listed as a similar specification replacement. Note that the substitute uses an SSOP-5 package instead of SSOP-3, requiring layout adaptation. The replacement offers adjustable delay rather than fixed delay, which may require circuit modification if the fixed timing was essential.

FAQ

Does the BU45K312G-TL require an external capacitor for the reset delay?

No, the device has a built-in counter timer delay circuit, so no external capacitor is necessary for setting the 200ms delay time.

What is the active state of the reset output?

The reset output is active low, meaning the open-drain output goes low when the detected voltage is below the threshold and the delay timer expires.