LDS3985M25R

Overview

The LDS3985M25R is a BiCMOS low-dropout linear voltage regulator manufactured by STMicroelectronics. It provides a fixed output voltage of 2.5 V with a maximum continuous load current of 300 mA. The device operates from an input voltage range of 2.5 V to 6 V and features ultra-low dropout characteristics, typically 150 mV at full load. Key electrical parameters include a typical quiescent current of 85 µA at no load and a shutdown mode current of less than 1.5 µA. It offers high power supply rejection ratios of 55 dB at 1 kHz and 50 dB at 10 kHz, along with low output noise of 30 µV RMS over the 10 Hz to 100 kHz bandwidth.

Feature Summary

• Ultra-low dropout voltage performance suitable for battery-powered systems
• Logic-controlled electronic shutdown function for standby power management
• Stable operation with low ESR ceramic capacitors
• Integrated internal current and thermal limiting protection

Applications

• Mobile phones and similar battery-powered wireless systems
• Portable information appliances
• Low power applications requiring efficient local regulation

Procurement Notes

Verify the specific suffix 'M25R' against official STMicroelectronics documentation to confirm the fixed 2.5 V output voltage and reel packaging configuration. Ensure compatibility with the required PCB footprint for the DFN6 package. Cross-reference the datasheet revision date to validate all electrical specifications before finalizing procurement orders.

Selection Notes

Select this component when a fixed 2.5 V rail is required with up to 300 mA capability in a compact surface-mount package. Consider the LDS3985 series for designs prioritizing low quiescent current and extended battery life. Verify that the application input voltage remains within the 2.5 V to 6 V operational range to ensure proper regulation and dropout margins.

Part Context

This part belongs to the LDS3985 family of ultra-low drop and low noise BiCMOS voltage regulators. The family includes variants with different fixed output voltages ranging from 1.25 V to 5 V. These regulators are designed for mobile and portable electronics, offering high PSRR and fast turn-on times while maintaining stability with small ceramic output capacitors.

Replacement Considerations

Direct substitutes within the same family include other LDS3985 variants with different fixed output voltages, such as LDS3985M18R (1.8 V) or LDS3985PU15R (1.5 V), provided the system voltage requirements allow for adjustment. Ensure pinout and package dimensions remain identical for direct replacement.