STMicroelectronics LDK120M15R

Overview

LDK120M15R from STMicroelectronics is a 200 mA, 1.5 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 µVRMS, 10 Hz–100 kHz with 10 nF bypass) and logic-controlled shutdown (<1 µA OFF-mode current), targeting power-sensitive RF and analog circuitry in portable electronics.

For engineers reviewing the LDK120M15R datasheet, LDK120M15R pinout, LDK120M15R application, or LDK120M15R equivalent, key selection criteria include its ceramic-capacitor compatibility (1 µF COUT), thermal shutdown (160 °C), internal current limiting, and SOT23-5L package suitability for space-constrained battery-powered designs.

Technical Context

The LDK120M15R employs a PMOS pass transistor architecture enabling ultra-low dropout and minimal quiescent current across temperature. Its feedback loop is internally compensated for stability with 1 µF ceramic output capacitors, eliminating need for ESR tuning.

Logic-controlled enable (EN) pin provides precise system-level power sequencing, while integrated short-circuit constant-current limiting and thermal protection ensure robust fault handling without external components.

Key Specifications

Pinout & Package

LDK120M15R is packaged in SOT23-5L - a 2.95 mm × 1.60 mm surface-mount package with 0.95 mm pitch, optimized for high-density portable PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B152MR-G and RT9013-15GB, the LDK120M15R uniquely combines 200 mA capability, 100 mV dropout, and 51 µVRMS noise with bypass support-making it optimal for noise-sensitive, battery-constrained systems where every millivolt of headroom and microvolt of ripple matters.

Availability

LDK120M15R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable medical monitors requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant packaging.

Supply support for LDK120M15R 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, and analog devices 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 regulation in space- and power-constrained portable electronics.

FAQ

What is the minimum input voltage required for LDK120M15R to maintain regulation at full 200 mA load?

The LDK120M15R requires VIN ≥ VOUT + VDROP. At 200 mA and 125 °C, dropout is up to 300 mV per datasheet Table 4. Thus, minimum input is 1.5 V + 0.3 V = 1.8 V. However, the absolute minimum specified operating input is 1.9 V - so 1.9 V is the guaranteed functional floor across temperature and process variation.

Can the BYP pin be left unconnected on the LDK120M15R?

Yes. Per Table 1, the BYP pin on fixed-output versions is optional for noise reduction. If unused, it must be left floating with no PCB routing - not tied to GND or OUT. Adding a 10 nF capacitor between BYP and GND reduces output noise from 148 µVRMS to 51 µVRMS but is not required for basic regulation.

Does LDK120M15R require an input capacitor, and if so, what value and type?

Yes. A 1 µF X5R or X7R ceramic capacitor is recommended at the IN pin (per Figure 3 and Section 6). This stabilizes the input rail during load transients and reduces high-frequency noise coupling. Larger values (up to 10 µF) are acceptable but not necessary for stability.

Is the LDK120M15R pin-compatible with other variants in the LDK120 family, such as adjustable or different output voltages?

Yes - all LDK120 variants (fixed and adjustable) share identical pinouts across SOT23-5L, SOT323-5L, and DFN6 packages. The only functional difference is pin 4: BYP (fixed) vs. ADJ (adjustable) vs. NC (some DFN variants). Layouts designed for LDK120M15R can accommodate other fixed-output versions without modification.