LDK120C31R

Overview

The LDK120C31R is a fixed-output low-dropout linear voltage regulator manufactured by STMicroelectronics. It provides a stable 3.1V output with a maximum load current of 200mA. The device operates from an input voltage range of 1.9V to 5.5V. Key electrical specifications include a typical dropout voltage of 100mV at 100mA and a maximum quiescent current of 100µA. It features a Power Supply Rejection Ratio (PSRR) of 55dB across the 120Hz to 10kHz frequency range. The component is housed in a compact SOT-323-5 surface-mount package.

Feature Summary

• Provides fixed 3.1V output with 200mA maximum current capacity
• Operates within a wide input voltage range of 1.9V to 5.5V
• Features low quiescent current for efficient power management
• Includes overcurrent and thermal overload protection mechanisms

Applications

• Battery-powered portable electronic devices
• Low noise analog circuit power supplies
• Embedded systems requiring stable voltage regulation
• Consumer electronics with space-constrained designs

Procurement Notes

Verify the specific suffix 'C31' confirms the 3.1V fixed output variant, as the LDK120 series includes multiple voltage options. Ensure compatibility with the SOT-323-5 footprint during PCB layout. Confirm RoHS compliance status if required by your manufacturing standards. Cross-reference the manufacturer part number with authorized distributors to avoid counterfeit components. Check for any recent product change notifications regarding packaging or sourcing.

Selection Notes

Select this component when a fixed 3.1V rail is required with minimal board space. The low dropout characteristic makes it suitable for battery applications where input voltage may approach the output level. Consider the 200mA current limit against peak load requirements. The SOT-323-5 package offers a small form factor compared to larger regulators. Evaluate thermal performance based on expected ambient temperatures and load currents.

Part Context

The LDK120 series comprises a family of low-dropout linear regulators designed for efficiency and noise reduction. This specific model, LDK120C31R, belongs to the fixed-output subset, distinguished by its 3.1V setting. Other variants in the series offer different fixed voltages or adjustable outputs. The series is characterized by low quiescent current and high PSRR, targeting applications sensitive to power supply noise.

Replacement Considerations

Direct substitutes must match the 3.1V output, 200mA current rating, and SOT-323-5 package. Verify pinout compatibility before substitution. Alternative LDOs from other manufacturers may require schematic adjustments due to differing control characteristics or protection thresholds.