STMicroelectronics STLQ015M21R

Overview

STLQ015M21R from STMicroelectronics is a 2.1 V fixed-output, 150 mA ultra-low-quiescent-current linear voltage regulator in SOT23-5L package. It operates from 1.5 V to 5.5 V input, delivers ±2% output accuracy at 25 °C, features 112 mV typical dropout at full load, and supports logic-controlled shutdown with 1 nA OFF-mode current. It powers microcontroller cores and sensors in battery-constrained portable devices.

For engineers reviewing the STLQ015M21R datasheet, STLQ015M21R pinout, STLQ015M21R application, or STLQ015M21R equivalent, key selection criteria include quiescent current vs. load/temperature, dropout behavior across input voltage range, ceramic capacitor stability (1 µF), thermal protection response, and enable logic thresholds for low-power sequencing.

Technical Context

This LDO employs a P-channel MOSFET pass element with internal reference, error amplifier, and thermal/current limiting circuitry. Its architecture enables stable regulation down to 0.8 V output while maintaining sub-2 µA quiescent current across -40 °C to 125 °C junction temperature.

The device integrates an enable input (VEN) that directly controls the pass transistor gate via internal logic, ensuring fast turn-on (160 µs) and true zero-current shutdown. Output noise is 75 µVRMS (10–100 kHz), and supply voltage rejection reaches 40 dB at 1 kHz for 0.8 V output.

Key Specifications

Pinout & Package

SOT23-5L package: 2.95 mm × 1.60 mm × 1.45 mm body height, 0.95 mm pitch, thermally enhanced die pad (exposed copper not connected internally).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar ultra-low-IQ LDO applications.

Compared with XC6206P212MR and RT9013-21GB, STLQ015M21R uniquely balances ultra-low load-dependent IQ (1.4 µA), integrated thermal protection, and standard active-high enable-all in pin-compatible SOT23-5L-making it optimal for safety-critical, long-life portable medical and industrial sensors.

Availability

STLQ015M21R is available at Aetrix Electronics and suitable for wearable health monitors, industrial wireless sensor nodes, smart home motion detectors, and portable medical glucose meters requiring stable component supply across extended product lifecycles.

Supply support for STLQ015M21R 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 analog, microcontroller, power, and sensing solutions for industrial, automotive, and consumer markets.

The STLQ015 series belongs to ST's ultra-low-power LDO family, engineered specifically for battery-operated IoT endpoints where multi-year operation and reliable shutdown behavior are non-negotiable design requirements.

FAQ

What is the minimum input voltage required for regulation at 2.1 V output?

The STLQ015M21R maintains regulation when input voltage is at least 2.212 V (2.1 V + 112 mV dropout) at 150 mA load and 25 °C. At full temperature range (-40 °C to 125 °C), worst-case dropout rises to 300 mV, requiring VIN ≥ 2.4 V for guaranteed 2.1 V output under max load.

Can the STLQ015M21R be used with a 0.47 µF output capacitor?

No-0.47 µF is below the minimum stable capacitance. The datasheet specifies 0.47 µF as the lower bound only when combined with specific ESR (0.056–6 Ω); stability is guaranteed only with ≥1 µF ceramic capacitor. Using 0.47 µF risks oscillation or poor transient response.

Does the NC pin require PCB layout treatment?

Yes-the NC (pin 4) is electrically unconnected but occupies a physical pad in the SOT23-5L mold. It must remain unconnected on the PCB: no trace, no solder mask opening, and no thermal relief. Routing near it is permitted, but grounding or tying to GND violates the internal isolation design.

How does the enable pin behave during power-up?

The EN pin has no internal pull-up or pull-down. If left floating during power-up, the device enters undefined state and may oscillate or fail to start. A 100 kΩ pull-down resistor to GND ensures reliable OFF-state default; active control requires clean logic-level drive from MCU GPIO or PMIC sequencer.