STMicroelectronics LK112SM60TR

Overview

LK112SM60TR from STMicroelectronics is a low-noise, low-dropout linear voltage regulator with shutdown control, designed for precision power management in space-constrained applications. It delivers up to 200 mA output current, maintains ≤500 mV dropout at full load, achieves ±2% output voltage accuracy at 25 °C, and supports 6.0 V fixed output. It is used in battery-powered sensor nodes requiring ultra-low quiescent current (0.1 µA in OFF mode) and low-noise analog supply rails.

For engineers reviewing the LK112SM60TR datasheet, LK112SM60TR pinout, LK112SM60TR application, or LK112SM60TR equivalent, key selection criteria include its SOT23-5L package footprint, TTL/CMOS-compatible SHDN input, 30 µVrms output noise (10 Hz–80 kHz), thermal and short-circuit protection, and input voltage range of 6.5 V to 14 V (VOUT + 0.5 V minimum).

Technical Context

The LK112SM60TR employs an internal PNP pass transistor to achieve low dropout and high PSRR (55 dB at 400 Hz). Its shutdown function accepts logic-level inputs (ON ≥1.8 V, OFF ≤0.6 V), enabling precise system-level power sequencing.

It integrates internal current limiting and thermal shutdown (trip point <150 °C), with output stability ensured by external 2.2 µF output capacitor and optional 0.1 µF bypass capacitor on the BYPASS pin to reduce noise to 30 µVrms.

Key Specifications

Pinout & Package

Supplied in SOT23-5L package (2.95 mm × 1.60 mm × 1.30 mm), optimized for thermal dissipation via internal die attach flag connection to GND pin.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AP2112K-6.0TRG1 and MCP1703T-6002E/MB, the LK112SM60TR uniquely combines 0.1 µA shutdown IQ, 30 µVrms noise via bypass pin, and integrated thermal shutdown - making it optimal for long-life, noise-sensitive, thermally unmanaged deployments.

Availability

LK112SM60TR is available at Aetrix Electronics and suitable for portable medical sensors, industrial IoT edge nodes, smart metering modules, and automated test equipment probes requiring stable component supply and long-term manufacturability.

Supply support for LK112SM60TR 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 ICs, sensors, and analog components for industrial, automotive, and consumer markets.

The LK112S series targets ultra-low-power, low-noise linear regulation in space-constrained systems - emphasizing extended battery life, precision analog integrity, and robustness in unregulated input environments.

FAQ

What is the minimum input voltage required for stable 6.0 V output?

The LK112SM60TR requires VIN ≥ VOUT + 0.5 V = 6.5 V for stable regulation. Below this threshold, dropout behavior begins; at 200 mA load, dropout voltage reaches 0.5 V maximum, so 6.5 V input sustains regulation down to that current. Input below 6.5 V risks output collapse or instability.

Can the Bypass pin be left unconnected?

Yes, the Bypass pin may be left floating or tied to GND if ultra-low noise is not required. However, omitting the 0.1 µF capacitor increases output noise from 30 µVrms to ~60 µVrms (typical). For precision analog circuits, ST recommends populating the bypass capacitor to meet the specified noise performance.

Does the LK112SM60TR support reverse polarity protection?

No, the LK112SM60TR does not include reverse polarity protection. Applying negative voltage to IN or SHDN beyond –0.3 V relative to GND may damage the device. External protection (e.g., series Schottky diode or MOSFET-based ideal diode) is required in systems prone to incorrect battery insertion or field wiring errors.

How does thermal shutdown behave under continuous overload?

Under sustained overload, the LK112SM60TR's thermal shutdown activates when junction temperature exceeds ~150 °C, disabling the output. After cooling below ~135 °C (typical hysteresis), the device automatically recovers. This cycle repeats until fault condition clears - preventing permanent damage but causing intermittent output loss during overload.