STMicroelectronics LK112M15TR

Overview

LK112M15TR from STMicroelectronics is a 1.5 V fixed-output, low-noise, low-dropout linear voltage regulator with integrated shutdown control and internal PNP pass transistor. It delivers up to 150 mA output current with 350 mV dropout at full load, 30 µV_rms output noise (10 Hz–80 kHz), and quiescent current as low as 0.1 µA in OFF mode. It is used in battery-powered sensor nodes requiring stable, ultra-low-power 1.5 V supply.

For engineers reviewing the LK112M15TR datasheet, LK112M15TR pinout, LK112M15TR application, or LK112M15TR equivalent, key selection criteria include dropout voltage at 150 mA, shutdown leakage (<0.1 µA), output noise performance with 0.1 µF bypass capacitor, and SOT23-5L thermal resistance (R_thJA = 255 °C/W).

Technical Context

The LK112M15TR employs an internal PNP pass transistor architecture enabling low dropout operation down to 290 mV at 150 mA while maintaining stability with minimal external capacitance (2.2 µF output, 1 µF input). Its TTL/CMOS-compatible SHDN pin allows logic-level enable/disable control with sub-100 nA shutdown current.

It integrates overcurrent and thermal shutdown protection, with junction temperature limited to <150 °C and short-circuit current foldback. The dedicated Bypass pin accepts a 0.1 µF capacitor to reduce output noise to 30 µV_rms, making it suitable for noise-sensitive analog signal chains.

Key Specifications

Pinout & Package

Supplied in compact SOT23-5L package (2.95 mm × 1.60 mm × 1.45 mm), optimized for space-constrained PCB layouts and thermal dissipation (R_thJA = 255 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, low-I_q LDO applications.

Compared with TPS78015DRVR and MCP1700T-1502E/TT, the LK112M15TR uniquely balances ultra-low OFF current (0.1 µA), low-noise operation (30 µV_rms via bypass pin), and logic-controllable shutdown - making it optimal for mixed-signal battery-powered systems demanding both precision analog supply and aggressive power gating.

Availability

LK112M15TR is available at Aetrix Electronics and suitable for wearable health sensors, industrial wireless transmitters, portable gas detectors, and smart meter backup power rails requiring stable component supply and long-term manufacturability.

Supply support for LK112M15TR includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, analog chips, and MEMS sensors for industrial, automotive, and consumer markets.

The LK112 series belongs to ST's precision low-dropout regulator product line, engineered specifically for ultra-low-power, noise-sensitive applications in battery-operated instrumentation and portable electronics.

FAQ

What is the minimum input voltage required for regulation at 150 mA output?

The LK112M15TR requires input voltage ≥1.85 V to maintain 1.5 V output at 150 mA, based on its maximum dropout voltage of 350 mV. For reliable operation across temperature and process variation, ST recommends ≥2.0 V input under full load. Input below 2.5 V is permitted only for V_OUT < 2 V devices per datasheet Section 3.

Can the BYPASS pin be left unconnected?

Yes, the BYPASS pin may be left floating or unconnected, but doing so results in higher output noise - typically 80–100 µV_rms instead of the specified 30 µV_rms. ST specifies 0.1 µF between BYPASS and GND to achieve the low-noise performance; omitting this capacitor degrades noise performance without affecting regulation or stability.

Does the LK112M15TR require an input capacitor?

Yes, ST specifies a minimum 1 µF ceramic input capacitor (CI) placed close to the IN and GND pins to ensure stability and suppress input transients. Omitting CI may cause oscillation or degraded line transient response, especially when powered from high-impedance sources like batteries or long PCB traces.

Is the shutdown function debounced or glitch-immune?

No internal debounce or glitch filtering is implemented on the SHDN pin. The device responds immediately to logic transitions, with propagation delay <10 µs. External RC filtering or firmware-controlled GPIO debouncing is recommended in noisy environments to prevent unintended toggling during power-up or ESD events.