STMicroelectronics LDK120M12R

Overview

LDK120M12R from STMicroelectronics is a 200 mA, 1.2 V fixed-output low-dropout (LDO) regulator in SOT23-5L package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and 100 µA max quiescent current. It delivers ultra-low noise (51 µVRMS, 10 Hz–100 kHz with 10 nF bypass) and logic-controlled shutdown (<1 µA OFF-mode current), optimized for power-sensitive portable electronics.

For engineers reviewing the LDK120M12R datasheet, LDK120M12R pinout, LDK120M12R application, or LDK120M12R equivalent, key selection criteria include dropout performance under 200 mA load, ceramic capacitor compatibility (1 µF min COUT), thermal shutdown threshold (160 °C), enable logic thresholds (0.4 V low / 1.2 V high), and noise-sensitive analog rail requirements in battery-powered systems.

Technical Context

The LDK120M12R employs a PMOS pass transistor architecture enabling ultra-low dropout and near-zero gate-drive current, eliminating external bias 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).

Noise suppression is achieved via dual-path design: the fixed version supports optional 10 nF bypass capacitor on BYP pin to reduce output noise to 51 µVRMS; without bypass, noise rises to 148 µVRMS. Supply voltage rejection remains 55 dB (120 Hz–10 kHz) regardless of bypass configuration.

Key Specifications

Pinout & Package

LDK120M12R is packaged in SOT23-5L (1.6 mm × 2.9 mm × 1.3 mm), a space-constrained surface-mount package with exposed pad for enhanced thermal dissipation (R_thJA = 160 °C/W). Pin mapping is validated per STMicroelectronics DS9378 Rev 9, Figure 2 and Table 1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B122MR-G and RT9013-12GB, LDK120M12R uniquely balances ultra-low noise (51 µVRMS), integrated enable, and minimal dropout (100 mV) in the smallest footprint (SOT23-5L), making it optimal for space- and noise-constrained battery-powered edge devices.

Availability

LDK120M12R is available at Aetrix Electronics and suitable for wearable health monitors, BLE peripherals, industrial wireless sensors, and smart home motion detectors requiring stable component supply, long-lifecycle support, and RoHS-compliant packaging.

Supply support for LDK120M12R 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The LDK120 series belongs to ST's precision low-noise LDO portfolio, engineered specifically for ultra-low-power, noise-sensitive applications in portable and battery-operated equipment where efficiency, size, and signal integrity are critical.

FAQ

What is the minimum input voltage required to maintain regulation at 1.2 V output and 200 mA load?

The LDK120M12R requires VIN ≥ VOUT + VDROP. At 200 mA and 40–125 °C, maximum dropout is 300 mV per Table 4. Thus, minimum input is 1.2 V + 0.3 V = 1.5 V. For reliable operation across temperature and process variation, ST recommends VIN ≥ 1.6 V at full load.

Can the BYP pin be left unconnected without affecting stability or regulation?

Yes. The BYP pin is optional for noise reduction only. When unused, it must be left floating with no PCB trace - not tied to GND or OUT. Stability is fully maintained with standard 1 µF COUT; bypass capacitor usage solely improves noise performance (51 µVRMS vs. 148 µVRMS).

Does LDK120M12R support ceramic output capacitors with ESR below 10 mΩ?

Yes. Unlike older LDOs, the LDK120M12R is explicitly designed for low-ESR ceramic capacitors (1 µF typical, 1–22 µF supported). Its internal compensation ensures stability with ESR as low as 1 mΩ, verified in Figure 25 (stability region) and Section 6 of DS9378 Rev 9.

How does thermal shutdown behave during sustained overload, and is there automatic recovery?

Thermal shutdown activates at 160 °C junction temperature with 20 °C hysteresis. Once tripped, the device shuts off output and cools; it automatically resumes regulation when junction temperature falls to ~140 °C. No external reset or enable toggling is required for recovery.