STMicroelectronics LDK120M29R

Overview

LDK120M29R from STMicroelectronics is a 200 mA, 2.9 V fixed-output low-dropout linear regulator with 100 mV typical dropout at 100 mA, 100 µA max quiescent current, ±2.0% output voltage tolerance at 25 °C, and operation from 1.9 V to 5.5 V input. It delivers ultra-low noise (51 µV_RMS, 10 Hz–100 kHz with 10 nF bypass) and logic-controlled shutdown (<1 µA OFF-mode current), targeting power rails in compact battery-powered systems.

For engineers reviewing the LDK120M29R datasheet, LDK120M29R pinout, LDK120M29R application, or LDK120M29R equivalent, this page provides verified package mapping (SOT23-5L), validated pin functions, confirmed thermal shutdown (160 °C), ceramic-capacitor stability (1 µF C_OUT), and real-world load regulation (0.006 %/mA).

Technical Context

The LDK120M29R employs a PMOS pass transistor architecture enabling ultra-low dropout and compatibility with ceramic output capacitors without ESR requirements. Its internal bandgap reference and error amplifier deliver tight DC accuracy (±2.0% at 25 °C) and stable line/load regulation (0.05 %/V and 0.006 %/mA).

It integrates logic-level enable control (V_EN high = active, low = shutdown), thermal foldback protection (160 °C trip with 20 °C hysteresis), and short-circuit current limiting (400 mA typical). The device operates across –40 °C to +125 °C junction temperature with R_thJA = 160 °C/W in SOT23-5L.

Key Specifications

Pinout & Package

LDK120M29R is packaged in SOT23-5L (ECOPACK®), a 5-pin surface-mount package measuring 2.95 mm × 1.60 mm × 1.45 mm with 0.95 mm pin pitch. It features exposed pad thermal enhancement and RoHS-compliant matte tin lead finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDK120M29R, the XC6219B292MR-G trades enable functionality for lower IQ, while the ADP160ACBZ-2.9-R7 offers lower noise and IQ but sacrifices 50 mA output capacity and increases dropout by 90 mV - making LDK120M29R optimal for 200 mA, enable-controlled, low-noise battery rails.

Availability

LDK120M29R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, cordless phones, and other battery-powered systems requiring stable component supply, long shelf-life assurance, and full production lifecycle support through July 2026.

Supply support for LDK120M29R 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 high-performance LDO portfolio, engineered specifically for ultra-low-noise, low-quiescent-current power delivery in space-constrained, battery-operated portable electronics.

FAQ

What is the minimum input voltage required for LDK120M29R to maintain regulation at 200 mA load?

The minimum input voltage is calculated as V_OUT + V_DROP. At 200 mA and 40–125 °C, V_DROP is up to 300 mV per datasheet Table 4. Thus, VIN(min) = 2.9 V + 0.3 V = 3.2 V. Below this, output voltage drops below regulation. This ensures reliable operation across temperature and load extremes.

Can LDK120M29R be used with a 1 µF ceramic output capacitor without an external bypass capacitor?

Yes - the device is stable with only a 1 µF ceramic C_OUT (no BYP cap required). However, omitting the 10 nF BYP capacitor increases output noise from 51 µV_RMS to 148 µV_RMS (per Table 4 note 2), so BYP is recommended for noise-sensitive analog/RF rails.

Does LDK120M29R require a specific PCB layout for thermal performance in SOT23-5L?

Yes - the SOT23-5L package has an exposed thermal pad (pin 2 GND). For optimal thermal resistance (R_thJA = 160 °C/W), the pad must be soldered to a ≥25 mm² copper pour connected to ≥2 internal ground planes via ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart).

Is the enable pin (EN) 5 V tolerant when VIN = 3.3 V?

No - the absolute maximum rating for V_EN is V_IN + 0.3 V (Table 2). With VIN = 3.3 V, V_EN must not exceed 3.6 V. Applying 5 V directly risks permanent damage. A resistive divider or level-shifter is required for 5 V logic interfacing.