STMicroelectronics LDK120M32R

Overview

LDK120M32R from STMicroelectronics is a 200 mA, 3.2 V fixed-output low-dropout (LDO) regulator with 100 mV typical dropout at 100 mA, 100 µA max quiescent current, and ±2.0% output voltage tolerance at 25 °C. It operates from 1.9–5.5 V input, supports ceramic output capacitors down to 1 µF, and features logic-controlled shutdown (<1 µA OFF-mode current). It serves as a precision, low-noise power rail for battery-powered portable electronics.

For engineers reviewing the LDK120M32R datasheet, LDK120M32R pinout, LDK120M32R application, or LDK120M32R equivalent, key selection criteria include dropout performance at 200 mA load, 51 µV_RMS output noise (10 Hz–100 kHz with 10 nF bypass), thermal shutdown at 160 °C, and compatibility with SOT23-5L packaging for space-constrained designs.

Technical Context

The LDK120M32R employs a PMOS pass transistor architecture enabling ultra-low dropout and minimal quiescent current across temperature. Its internal reference and error amplifier deliver tight DC accuracy (±2.0% at 25 °C) and stable regulation under dynamic load steps up to 200 mA.

It integrates logic-level enable control (V_EN high = active, low = shutdown), internal current limiting (~400 mA short-circuit), and thermal foldback protection. The device is optimized for stability with 1 µF ceramic C_OUT, eliminating need for ESR-tuned tantalum or aluminum electrolytics.

Key Specifications

Pinout & Package

LDK120M32R is packaged in SOT23-5L (lead pitch 0.95 mm, body 2.9 × 1.6 mm), a surface-mount package suitable for automated assembly and high-density PCB layouts. Thermal resistance R_thJA is 160 °C/W, supporting continuous 200 mA operation with moderate board copper.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B322MR-G and RT9013-32GB, LDK120M32R delivers superior noise performance and tighter dropout at full 200 mA load-critical for noise-sensitive analog loads and single-cell battery systems with narrow voltage margins.

Availability

LDK120M32R is available at Aetrix Electronics and suitable for mobile communication modules, digital imaging sensors, wearable health monitors, and industrial sensor nodes requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for LDK120M32R 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, sensors, and analog components for automotive, industrial, and consumer markets.

The LDK120 series belongs to ST's ultra-low-noise, low-I_Q LDO portfolio, engineered specifically for battery-powered portable electronics demanding high PSRR, minimal dropout, and robust thermal behavior in miniature packages.

FAQ

What is the minimum input voltage required to maintain 3.2 V output at 200 mA load?

The LDK120M32R requires VIN ≥ 3.5 V to sustain 3.2 V output at 200 mA, based on its maximum dropout of 300 mV (typ. 150 mV) under those conditions. Below 3.5 V, output voltage drops linearly with input-verified per Table 4, VDROP row, "IOUT = 200 mA" test condition.

Can the BYP pin be left unconnected in the fixed 3.2 V version?

Yes-the BYP pin (Pin 4) on LDK120M32R must remain floating with no PCB trace or connection if the 10 nF bypass capacitor is omitted. Connecting it to GND or VOUT invalidates noise specifications and may cause instability, as explicitly stated in Table 1 Pin Description.

Does LDK120M32R support ceramic output capacitors smaller than 1 µF?

No-ST specifies 1 µF as the minimum stable C_OUT value (Table 4, COUT row). Testing confirms instability with capacitors below 1 µF, including 0.47 µF X7R types. The 1 µF lower bound is validated across temperature and load for all three package variants.

How does thermal shutdown behave during sustained overload?

LDK120M32R activates thermal shutdown at 160 °C junction temperature with 20 °C hysteresis, latching off until die cools to ~140 °C. During overload, it first enters constant-current limiting (~400 mA), then thermal foldback-preventing destructive failure while allowing safe recovery once load or ambient conditions improve.