LD3985G27R

Overview

The LD3985G27R is a fixed-output low-dropout linear regulator manufactured by STMicroelectronics, providing a stable 2.7 V output voltage. It supports a maximum output current of 150 mA and operates within an input voltage range of 2.5 V to 6 V. The device features ultra-low dropout characteristics, with typical values of 60 mV at 150 mA load and 0.4 mV at 1 mA load. Quiescent current is typically 85 μA at no load and 170 μA at full load, dropping to a maximum of 1.5 μA in shutdown mode. It includes logic-controlled electronic shutdown, internal current limiting, and thermal protection. The regulator is designed for stability with low ESR ceramic capacitors and offers high power supply rejection ratios exceeding 60 dB at low frequencies.

Feature Summary

• Ultra-low quiescent current consumption extending battery life in portable applications
• Logic-controlled electronic shutdown function for standby power management
• Stable operation with low ESR ceramic capacitors
• Integrated internal current limit and thermal overload protection

Applications

• Battery-powered wireless systems
• Mobile phones
• Low-power embedded devices

Procurement Notes

Verify the specific suffix 'G27R' against official STMicroelectronics documentation to confirm the 2.7 V fixed output voltage variant. Ensure compatibility with required PCB footprint dimensions for the TSOT-23 package. Confirm that the selected component meets the necessary environmental operating temperature range specifications for the intended application environment.

Selection Notes

Select this component when a precise 2.7 V rail is required from a 2.5 V to 6 V source. Consider its low noise profile suitable for sensitive analog circuits. Evaluate the need for the shutdown pin functionality if system power management requires remote control of the regulator state. Verify capacitor ESR requirements to ensure loop stability under all load conditions.

Part Context

This part belongs to the LD3985 family of BiCMOS voltage regulators known for low noise and low dropout performance. The series is engineered for efficiency in battery-operated equipment where minimizing ground current during dropout is critical. Other variants in the family offer different fixed output voltages such as 1.2 V, 1.8 V, 2.5 V, 3.3 V, and 4.7 V, sharing identical package and protection features.

Replacement Considerations

Direct substitutes include other LD3985 variants with different output voltages if the voltage level can be adjusted externally, or compatible LDOs from the same manufacturer offering similar 150 mA output and TSOT-23 packaging. Verify pinout compatibility before substitution.