STMicroelectronics LDK220M50R

Overview

LDK220M50R from STMicroelectronics is a 5.0 V fixed-output, 200 mA low-dropout linear regulator in SOT23-5L package, featuring 100 mV typical dropout at 100 mA, ±2.0% output voltage tolerance at 25 °C, and logic-controlled shutdown with <1 µA off-mode current. It delivers stable power to noise-sensitive analog circuitry in space-constrained portable systems.

For engineers reviewing the LDK220M50R datasheet, LDK220M50R pinout, LDK220M50R application, or LDK220M50R equivalent, key selection criteria include dropout performance under 200 mA load, ceramic capacitor compatibility (1 µF), thermal shutdown threshold (160 °C), and enable-input logic thresholds (0.4 V low / 1.2 V high) for battery-powered system control.

Technical Context

The LDK220M50R integrates a bandgap reference, error amplifier, and PMOS pass transistor in a low-noise architecture optimized for stability with 1 µF ceramic output capacitors. Its internal current-limiting and thermal protection activate at 400 mA short-circuit current and 160 °C junction temperature, respectively.

It supports two operating modes: active regulation (EN ≥ 1.2 V) and ultra-low-power shutdown (EN ≤ 0.4 V), with an integrated 18 Ω output discharge resistor active during shutdown to prevent floating rail conditions - a critical feature absent in SOT-89 variants.

Key Specifications

Pinout & Package

LDK220M50R is packaged in SOT23-5L - a 5-pin, surface-mount plastic package measuring 2.95 mm × 1.60 mm × 1.45 mm (max height), with exposed pad not electrically connected. Thermal resistance is R_thJA = 160 °C/W (JEDEC 4-layer board).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV70750DBVR and AP2210K-5.0TRG1, LDK220M50R uniquely combines output discharge, 160 °C thermal shutdown, and 20 µV_RMS noise in a 5 V fixed-output SOT23-5L package - making it optimal for battery longevity, system-level power sequencing, and precision analog supply.

Availability

LDK220M50R is available at Aetrix Electronics and suitable for portable medical sensors, set-top box power rails, laptop embedded controllers, and industrial PLC I/O modules requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LDK220M50R 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 devices for automotive, industrial, and consumer markets.

The LDK220 series belongs to ST's high-performance LDO portfolio targeting ultra-low-noise, low-quiescent-current regulation in space-constrained battery-powered and industrial applications - emphasizing reliability, thermal robustness, and ease of integration with ceramic capacitors.

FAQ

What is the minimum input voltage required for LDK220M50R to maintain regulated 5.0 V output at 200 mA?

The minimum input voltage is calculated as V_OUT + V_DROP = 5.0 V + 350 mV = 5.35 V, based on the maximum dropout voltage of 350 mV specified at 200 mA and 40–125 °C. Below this, output voltage collapses linearly with input.

Can LDK220M50R be used with a 10 µF ceramic output capacitor?

Yes - the device is stable with output capacitance from 1 µF to 22 µF per Table 6 and Figure 22. A 10 µF X7R ceramic capacitor (ESR <1 Ω) improves load-transient response without compromising phase margin, provided PCB layout maintains short traces and solid ground plane.

Is the ADJ pin on LDK220M50R functional or should it be left unconnected?

The ADJ pin is not connected internally on the LDK220M50R (fixed 5.0 V version) and must be left floating or tied to GND per best practice - though the datasheet confirms it has no electrical function. It is not a feedback node and does not affect regulation.

Does LDK220M50R support reverse-voltage protection on the output pin?

No - the device lacks reverse-battery or reverse-output protection. Applying voltage to VOUT while EN is low may damage the internal discharge transistor. The datasheet explicitly warns against external voltage on VOUT during shutdown (Section 2, footnote *).