STMicroelectronics LDK220C50R

Overview

LDK220C50R from STMicroelectronics is a 5.0 V fixed-output, 200 mA low-dropout linear regulator in SOT23-5L package, featuring 100 mV 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 devices.

For engineers reviewing the LDK220C50R datasheet, LDK220C50R pinout, LDK220C50R application, or LDK220C50R equivalent, key selection criteria include dropout performance under 200 mA load, ceramic-capacitor compatibility (1 µF), thermal shutdown threshold (160 °C), EN pin logic thresholds (0.4 V low / 1.2 V high), and package-specific thermal resistance (R_thJA = 160 °C/W for SOT23-5L).

Technical Context

The LDK220C50R employs a bandgap-referenced op-amp control loop with internal current limiting and thermal protection. Its enable input directly gates the pass transistor bias, enabling fast turn-on/turn-off with controlled discharge via an internal 18 Ω resistor when EN is low.

Designed for fixed-output operation, it omits the ADJ pin functionality present in adjustable variants-pin 4 is NC-and relies on factory-trimmed feedback for 5.0 V ±2.0% accuracy across -40 °C to 125 °C. Output stability is guaranteed with 1 µF ceramic capacitors and ESR ≤10 Ω.

Key Specifications

Pinout & Package

LDK220C50R is supplied in SOT23-5L package (3.0 × 1.7 × 1.3 mm, 5-pin surface-mount). Thermal resistance is R_thJA = 160 °C/W (JEDEC 4-layer board), enabling 200 mA operation up to +85 °C ambient without heatsinking.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV70550DBVR and MCP1700T-5002E/MB, LDK220C50R uniquely combines 125 °C operation, integrated discharge, and 100 mV dropout in a thermally efficient SOT23-5L package-making it optimal for automotive-adjacent and high-reliability portable designs where thermal margin and safe shutdown are non-negotiable.

Availability

LDK220C50R is available at Aetrix Electronics and suitable for battery-powered equipment, set-top boxes, and industrial PLC I/O modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for LDK220C50R 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 LDK220 series targets ultra-low-power, noise-sensitive applications in portable and industrial electronics-emphasizing dropout efficiency, thermal robustness, and seamless integration with ceramic capacitors.

FAQ

What is the minimum input voltage required for LDK220C50R to regulate 5.0 V output?

The LDK220C50R requires a minimum input voltage of 5.1 V to maintain regulation at full 200 mA load, based on its 100 mV typical dropout voltage. At lighter loads (e.g., 10 mA), regulation is sustained down to 5.05 V input. Below 5.0 V input, the device enters dropout and output tracks input minus ~180 mV.

Can LDK220C50R be used with a 10 µF aluminum electrolytic capacitor instead of ceramic?

No-aluminum electrolytic capacitors are not recommended. The LDK220C50R's stability is characterized and guaranteed only with 1–22 µF ceramic capacitors having ESR ≤10 Ω. Aluminum electrolytics typically exceed 100 mΩ ESR and introduce phase lag that risks oscillation; using them voids stability assurance per DS10219 Section 6.

Is the EN pin 5 V tolerant when driven by a microcontroller GPIO?

Yes-the EN pin accepts voltages up to V_IN + 0.3 V per absolute maximum ratings, and V_IN can reach 13.2 V. When driven by a 3.3 V GPIO, EN sees VIH = 3.3 V > 1.2 V threshold, ensuring reliable activation. No level-shifting is needed for standard 1.8 V, 3.3 V, or 5 V logic interfaces.

Does LDK220C50R support reverse-current blocking when input is disconnected?

No-it lacks intrinsic reverse-current blocking. If V_OUT exceeds V_IN (e.g., during hot-swap or backup capacitor discharge), current flows backward through the pass transistor. The internal discharge resistor (18 Ω) only activates when EN = low; external reverse-blocking diodes or MOSFETs are required for bidirectional isolation.