LD2981ABU33TR

Overview

The LD2981ABU33TR is a fixed-output positive low-dropout linear voltage regulator manufactured by STMicroelectronics. It provides a stable 3.3 V output with a maximum current capability of 100 mA. The device operates within an input voltage range of 2.5 V to 16 V and features a typical dropout voltage of 1 mV at zero load, rising to a maximum of 3 mV. It maintains a tight output voltage tolerance of ±0.75% and draws a quiescent current of 100 µA. Designed for surface-mount assembly in a SOT-89-3 package, it functions reliably across an extended temperature range from -40 °C to +125 °C.

Feature Summary

• Ultra-low dropout voltage performance ensures efficient power regulation even with minimal input-to-output differential.
• Logic-controlled electronic shutdown via the inhibit pin allows for system standby modes with negligible current consumption.
• Integrated thermal and current limiting protection mechanisms safeguard the device under fault conditions.

Applications

• Battery-powered portable electronics requiring low quiescent current
• Cellular phones and personal digital assistants (PDAs)
• Laptop computers and palmtop devices

Procurement Notes

Verify the specific suffix 'BU' against the official datasheet to confirm the SOT-89-3 package configuration and tape-and-reel delivery format. Ensure the 'A' grade designation matches the required ±0.75% output voltage accuracy specification for your application. Confirm RoHS compliance status through the manufacturer's latest documentation before finalizing procurement orders.

Selection Notes

Select this component when a fixed 3.3 V rail is needed with high precision and minimal voltage drop. The SOT-89-3 package suits applications where moderate heat dissipation is required alongside compact footprint constraints. Consider the inhibit pin functionality if active power management or standby control is necessary for the system design.

Part Context

This part belongs to the LD2981 series of ultra-low-dropout regulators designed for low-noise, low-power applications. The series supports various fixed output voltages including 2.5 V, 3.0 V, 3.3 V, and 5.0 V. It is engineered to work with low ESR ceramic capacitors, making it suitable for modern compact electronic designs requiring stable power supplies.

Replacement Considerations

Cross-reference with other LD2981 variants such as LD2981CM33TR for different package options like SOT-23-5. Verify that substitute parts maintain the same 100 mA output current and 3.3 V fixed output voltage while matching the required operating temperature range and package dimensions.