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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LK112M32TR

Name: LK112M32TR
Brand: STMicroelectronics
SKU: LK112M32TR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LK112M32TR

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: SC-74A, SOT-753

Datasheet:: LK112M32TR.pdf

Description:: IC REG LINEAR 3.2V 150MA SOT23-5

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Product details

Overview

LK112M32TR from STMicroelectronics is a 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 µVrms output noise (10 Hz–80 kHz), and 250 µA max quiescent current in ON mode. It operates from input voltages as low as VOUT + 0.5 V (for VOUT > 2 V) and supports 3.2 V fixed output - ideal for powering noise-sensitive analog sensors and low-power microcontrollers in portable instrumentation.

For engineers reviewing the LK112M32TR datasheet, LK112M32TR pinout, LK112M32TR application, or LK112M32TR equivalent, key selection criteria include its ultra-low OFF-mode quiescent current (<0.1 µA), TTL/CMOS-compatible SHDN pin, 0.1 µF bypass-capacitor-supported noise reduction, thermal and short-circuit protection, and SOT23-5L package suitability for space-constrained PCB layouts.

Technical Context

The LK112M32TR uses 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 power sequencing.

Thermal shutdown activates below 150 °C junction temperature, and current limiting engages during overloads or short circuits. Output voltage stability is maintained across –40 °C to +125 °C operating junction temperature, with ±2% initial accuracy and 0.09 mV/°C temperature coefficient.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Voltage	Fixed 3.2 V ±2% - ensures stable biasing for 3.3 V-tolerant analog ICs without external feedback components.
Max Output Current	150 mA - sufficient to power multiple low-power MCUs, ADCs, or RF transceivers simultaneously.
Dropout Voltage	350 mV at 150 mA - enables operation from 3.55 V input when regulating 3.2 V, extending battery life in single-cell Li-ion or alkaline systems.
Quiescent Current	250 µA max (ON), 0.1 µA (OFF) - minimizes standby power loss in always-on sensor nodes and IoT endpoints.
Output Noise	30 µVrms (10 Hz–80 kHz, 0.1 µF bypass) - meets stringent noise requirements for precision op-amps and high-resolution SAR ADCs.
PSRR	55 dB at 400 Hz - suppresses ripple from switching DC/DC converters upstream of the LDO stage.
Operating Input Range	3.7 V to 14 V (VOUT = 3.2 V) - accommodates wide-input industrial supplies while maintaining regulation margin.

Pinout & Package

SOT23-5L package: compact 2.95 mm × 1.60 mm surface-mount outline with exposed die attach flag for enhanced thermal dissipation (R_thJA = 255 °C/W).

Pin/Terminal	Circuit Role	Design Meaning
1 - SHDN	Shutdown control input	TTL/CMOS-compatible enable pin; device active when ≥1.8 V, fully disabled when ≤0.6 V (I_SHDN ≤35 µA).
2 - GND	Power ground reference	Internally connected to die attach flag - lowers thermal resistance and improves power handling capability.
3 - Bypass	Noise reduction terminal	Accepts 0.1 µF capacitor to reduce output noise to 30 µVrms; decouples internal reference and error amplifier.
4 - OUT	Regulated output	3.2 V output with internal current and thermal limiting; requires ≥2.2 µF ceramic output capacitor for stability.
5 - IN	Input supply connection	Accepts 3.7–14 V DC; must exceed V_OUT + 0.5 V for regulation; internal ESD protection rated to 16 V absolute max.

Key Features

Feature	Design Value
Ultra-low OFF-mode IQ	≤0.1 µA enables multi-year battery life in maintenance-free remote sensors and energy-harvesting systems.
Integrated thermal shutdown	Activates below 150 °C junction temperature - prevents permanent damage during sustained overload or poor heatsinking.
Bypass-pin noise optimization	External 0.1 µF capacitor reduces broadband output noise by >50% versus standard LDO configurations.
Internal current limiting	Self-protecting 150 mA limit eliminates need for external fuse or current-sense circuitry in end equipment.
Wide input voltage range	Operates from 3.7 V to 14 V - compatible with unregulated wall adapters, automotive subsystems, and industrial 12 V rails.

Applications

Portable Medical Sensors

Industrial Process Transmitters

Use Scenario: Powering low-noise analog front-ends in handheld pulse oximeters and ECG monitors powered by coin-cell or Li-ion batteries.

IC Role / Device Role / Timing Role: Primary 3.2 V LDO supplying signal-chain components (op-amps, ADCs, reference buffers) with minimal added noise.

Use Value: 30 µVrms noise and <0.1 µA shutdown current extend battery runtime while preserving SNR in sub-µV biomedical signal acquisition.

Use Scenario: Regulating power for 4–20 mA loop-powered transmitters in factory automation and process control cabinets.

IC Role / Device Role / Timing Role: Local 3.2 V supply for microcontroller, DAC, and sensor interface ICs within isolated loop-powered modules.

Use Value: 350 mV dropout allows operation from marginal loop voltage (e.g., 6.8 V), and thermal shutdown protects against enclosure overheating.

Wireless Sensor Nodes

Low-Power MCU Subsystems

Use Scenario: Supplying 3.2 V to BLE SoCs and environmental sensors (temperature/humidity/pressure) in battery-operated IoT edge devices.

IC Role / Device Role / Timing Role: Always-on LDO with programmable shutdown, synchronized to radio duty cycling via SHDN pin.

Use Value: 250 µA ON-mode IQ and <0.1 µA OFF-mode IQ minimize average current draw during deep-sleep intervals.

Use Scenario: Providing clean 3.2 V rail to Cortex-M0+ microcontrollers and on-chip peripherals in embedded control modules.

IC Role / Device Role / Timing Role: Main system regulator delivering stable voltage during code execution, interrupt handling, and peripheral activation.

Use Value: ±2% output accuracy and 0.09 mV/°C drift ensure consistent timing and ADC reference performance across industrial temperature ranges.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
AP2210K-3.2TRG1	Higher dropout (500 mV @ 150 mA), higher noise (45 µVrms), no dedicated bypass pin.	Lacks noise-reduction flexibility; less suitable for ultra-low-noise analog chains.	Prefer when cost sensitivity outweighs noise and dropout requirements.
MCP1703T-3202E/MB	Lower quiescent current (2 µA ON), but no shutdown pin; fixed 3.2 V output with ±1% tolerance.	Cannot be externally disabled - unsuitable for dynamic power gating in battery systems.	Prefer where continuous regulation is required and shutdown is unnecessary.

Compared with AP2210K-3.2TRG1 and MCP1703T-3202E/MB, the LK112M32TR uniquely combines ultra-low OFF-mode IQ, a dedicated noise-bypass pin, and TTL-compatible shutdown - making it optimal for battery-constrained, noise-sensitive, and power-gated applications.

Availability

LK112M32TR is available at Aetrix Electronics and suitable for portable medical sensors, industrial process transmitters, and wireless sensor nodes requiring stable component supply, long-term manufacturability, and RoHS-compliant packaging.

Supply support for LK112M32TR 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 linear regulator product line, engineered specifically for ultra-low-noise, low-quiescent-current applications in battery-powered and signal-integrity-critical systems.

FAQ

What is the minimum input voltage required for regulation at 3.2 V output?

The LK112M32TR requires VIN ≥ VOUT + 0.5 V = 3.7 V for stable regulation. Below this threshold, dropout occurs and output voltage drops linearly with input. The device remains functional down to 2.5 V input but cannot maintain 3.2 V regulation below 3.7 V.

Can the Bypass pin be left floating or omitted?

No - the Bypass pin must be connected to a 0.1 µF ceramic capacitor to ground to achieve the specified 30 µVrms output noise. Leaving it floating increases noise to ~60 µVrms and may degrade transient response and reference stability.

Does the LK112M32TR require an input capacitor?

An input capacitor (CI ≥1 µF ceramic) is recommended per the datasheet to suppress high-frequency noise and improve line transient response. While not strictly mandatory for basic regulation, omission risks instability under fast input voltage changes or high-source-impedance conditions.

Is the SHDN pin internally pulled up or down?

The SHDN pin has no internal pull-up or pull-down. It must be actively driven to ≥1.8 V for ON state or ≤0.6 V for OFF state. Floating SHDN results in undefined operation - external pull-up or pull-down resistors are required in open-drain or undriven logic interfaces.

LK112M32TR Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: SC-74A, SOT-753

Packaging:: Tape & Reel (TR)

Product Status:: Obsolete

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 14V

Voltage - Output (Min/Fixed):: 3.2V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.35V @ 150mA

Current - Output:: 150mA

Current - Quiescent (Iq):: 250 µA

Current - Supply (Max):: -

PSRR:: 55dB (400Hz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -30°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: SOT-23-5

LK112M32TR FAQ

1.How can I place an order for LK112M32TR through Aetrix?

Please submit a Request for Quotation (RFQ) for LK112M32TR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LK112M32TR reliable?

The price and inventory of LK112M32TR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LK112M32TR is usually 5 days.

3.What payment methods are accepted for LK112M32TR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LK112M32TR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LK112M32TR?

LK112M32TR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LK112M32TR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LK112M32TR?

For technical support, including LK112M32TR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LK112M32TR requirements.

6.How does Aetrix verify that LK112M32TR is sourced from the original manufacturer or authorized distributors?

All LK112M32TR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LK112M32TR meets industry standards.

7.What is the process for return or replacement of LK112M32TR?

All LK112M32TR units undergo pre-shipment inspection (PSI). If there is an issue with LK112M32TR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LK112M32TR part is unused and in its original packaging.

Return procedure for LK112M32TR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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