LDLN025M45R

Overview

The LDLN025M45R is a 250 mA ultra-low noise low-dropout (LDO) linear voltage regulator manufactured by STMicroelectronics. It operates within an input voltage range of 1.5 V to 5.5 V and provides a fixed output voltage of 4.5 V with 2% accuracy across line, load, and temperature variations. The device features an ultra-low quiescent current of 12 μA at no-load and consumes less than 1 μA in shutdown mode via logic-controlled enable. It delivers high power supply rejection ratio (PSRR) of 80 dB at 100 Hz and maintains output noise below 6.5 μVRMS. Designed for stability with ceramic capacitors, it includes internal soft-start, overcurrent protection, thermal shutdown, and output discharge functions.

Feature Summary

• Ultra-low noise performance suitable for sensitive RF and analog loads
• Logic-controlled electronic shutdown for extended battery life
• High power supply rejection ratio for clean power delivery
• Integrated safety protections including thermal and short-circuit limits

Applications

• Noise-sensitive loads such as precision ADCs and sensors
• Voltage control oscillators (VCOs) in mobile phones and tablets
• Wireless LAN devices and wireless IoT modules

Procurement Notes

Verify the specific suffix 'M45R' against official STMicroelectronics documentation to confirm the fixed 4.5 V output voltage and SOT-23-5L surface-mount package configuration. Ensure compatibility with required ceramic output capacitance values for stability. Cross-reference the part number with authorized distributors to validate authenticity and avoid counterfeit components.

Selection Notes

Select this component when powering ultra-sensitive analog or RF circuits requiring minimal output noise and high PSRR. It is appropriate for space-constrained portable devices where low quiescent current extends battery standby time. Consider the 250 mA maximum output current and 1.5 V to 5.5 V input range constraints during system design.

Part Context

This part belongs to the LDLN025 series of 250 mA LDO regulators designed for noise-sensitive applications. The series offers various fixed output voltages from 1 V to 5 V in 50 mV steps. It is characterized by best-in-class output noise figures and very high PSRR, making it suitable for smartphones, smartwatches, fitness monitors, and medical sensors.

Replacement Considerations

Consult official STMicroelectronics substitution guides for verified equivalents. Generic LDO replacements may not match the specific ultra-low noise (<6.5 μVRMS) or high PSRR (80 dB @ 100 Hz) characteristics required for sensitive RF and analog loads.