LDK120M31R

Overview

The LDK120M31R is a low-dropout linear voltage regulator from STMicroelectronics, providing a fixed output voltage of 3.1 V with a maximum load current of 200 mA. It operates within an input voltage range of 1.9 V to 5.5 V and features a typical dropout voltage of 100 mV at 100 mA. The device ensures high precision with an output voltage tolerance of ±2.0% at 25 °C. Designed for efficiency, it exhibits a low quiescent current of 100 μA and consumes less than 1 μA in shutdown mode via logic-controlled enable. It includes internal short-circuit constant current limiting and thermal protection, ensuring robust performance across a temperature range of -40 °C to 125 °C.

Feature Summary

• Ultra-low dropout voltage capability (typical 100 mV) enables efficient operation even when input voltage approaches the output level.
• Logic-controlled electronic shutdown function allows deep sleep modes with total current consumption below 1 μA.
• Integrated safety mechanisms include constant current limiting for short-circuit protection and thermal shutdown for overload conditions.
• Compatible with small ceramic output capacitors (1 μF), facilitating compact printed circuit board layouts.

Applications

• Low-power battery-powered portable devices requiring extended runtime
• Embedded systems utilizing ultra-low quiescent current regulators
• Noise-sensitive analog circuits benefiting from very low noise profiles

Procurement Notes

Verify the specific suffix 'M' against official datasheets to confirm tape-and-reel packaging specifications and ensure compatibility with automated assembly processes. Confirm that the 3.1 V fixed output aligns precisely with target system requirements, as adjustable variants exist within the same family. Validate package integrity upon receipt to prevent damage to the delicate SOT23-5L or DFN6 leads during handling.

Selection Notes

Select this component when a stable 3.1 V rail is required with minimal voltage headroom loss. The LDK120 series offers wider fixed voltage options ranging from 0.8 V to 3.5 V; verify if alternative voltages better suit the design. Consider the SOT23-5L or DFN6 packages based on available footprint constraints. Ensure the application does not exceed the 200 mA continuous current limit or operate outside the specified -40 °C to 125 °C temperature range.

Part Context

The LDK120M31R belongs to the broader LDK120 family of low-dropout regulators designed for power-sensitive applications. This family emphasizes low static current and low noise, making it suitable for modern portable electronics. The M31R designation specifically indicates the 3.1 V fixed output variant packaged in reels, distinguishing it from adjustable versions or other fixed voltage outputs within the same regulatory architecture.

Replacement Considerations

Direct substitutes within the LDK120 family include other fixed voltage variants such as LDK120M33R (3.3 V) or LDK120M25R (2.5 V). For adjustable designs, the LDK120AJxx series provides programmable output capabilities. Verify pinout compatibility and thermal characteristics before swapping between different package types like SOT23-5L and DFN6.