LDS3985PU18RY

Overview

The LDS3985PU18RY is a BiCMOS low-dropout (LDO) voltage regulator manufactured by STMicroelectronics. It provides a fixed 1.8V output with a maximum continuous current of 300mA. The device operates within an input voltage range of 2.5V to 6V and features a typical dropout voltage of 150mV at full load. Key electrical characteristics include a quiescent current of 85µA, power supply rejection ratio (PSRR) of 55dB at 1kHz, and line regulation of 0.00756%/V. It is housed in a compact 6-DFN (3x3mm) package with an exposed pad for thermal management.

Feature Summary

• Ultra-low dropout voltage capability for efficient power conversion
• Low noise performance suitable for sensitive analog circuits
• Integrated shutdown control for power management optimization
• Built-in overcurrent and thermal protection mechanisms

Applications

• Portable battery-powered electronic devices
• RF modules requiring clean power supplies
• Embedded systems with strict power constraints
• Automotive infotainment subsystems

Procurement Notes

Verify the specific suffix 'PU18RY' to confirm the 1.8V fixed output, 6-DFN package, and tape-and-reel packaging configuration. Ensure compatibility with RoHS3 standards and check for end-of-life status or alternative sourcing options if production availability is limited. Confirm thermal pad soldering requirements for the DFN package during assembly.

Selection Notes

Select this component when a stable 1.8V rail is required from a 2.5V–6V source with minimal voltage drop. The 300mA output current supports moderate load demands while maintaining low quiescent current for battery efficiency. The 6-DFN package offers a small footprint ideal for space-constrained designs requiring robust thermal dissipation through the exposed pad.

Part Context

This part belongs to the LDS3985 family of ultra-low-dropout regulators designed for high-performance applications. The series includes various fixed output voltages and packages, catering to diverse power management needs in consumer electronics and automotive sectors. The BiCMOS technology ensures low noise and high PSRR, distinguishing it from standard CMOS LDOs.

Replacement Considerations

Direct substitutes may include other LDS3985 variants with different output voltages or packages, such as LDS3985M18R. Verify pinout compatibility and thermal characteristics before substitution. Cross-reference with similar 300mA LDOs from other manufacturers only if electrical parameters and package dimensions match exactly.