STMicroelectronics LDK220U50R

Overview

LDK220U50R from STMicroelectronics is a 5.0 V fixed-output, 200 mA low-dropout linear regulator in SOT-89 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 consumer and industrial systems.

For engineers reviewing the LDK220U50R datasheet, LDK220U50R pinout, LDK220U50R application, or LDK220U50R equivalent, key selection criteria include dropout voltage under 200 mA load, thermal performance in SOT-89 (R_thJA = 110 °C/W), ceramic capacitor compatibility (C_OUT = 1 µF), and enable-input logic thresholds across -40 °C to 125 °C.

Technical Context

The LDK220U50R implements a bandgap-referenced op-amp control loop with internal current limiting and thermal shutdown (trip point 160 °C, 20 °C hysteresis). Its architecture supports fast transient response-load step recovery time <200 µs-and integrates an active output discharge resistor (18 Ω) activated when EN is low.

Unlike adjustable versions, the U50R variant uses a trimmed internal resistor divider for 5.0 V output and omits the ADJ pin; it is only available in SOT-89, where pin 1 = OUT, pin 2 = GND, pin 3 = IN-no EN or ADJ terminals. This simplifies layout but removes logic control and programmability.

Key Specifications

Pinout & Package

SOT-89 package: 3-pin thermally enhanced plastic outline with exposed tab (pin 2 connected to GND internally); footprint requires thermal pad soldering for optimal R_thJA = 110 °C/W performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV70550DBVR and MCP1700T-5002E/MB, the LDK220U50R offers superior thermal performance in SOT-89 and lowest dropout for marginal input conditions, while sacrificing enable functionality and ultra-low IQ-making it optimal for thermally demanding, fixed-voltage, medium-current roles.

Availability

LDK220U50R is available at Aetrix Electronics and suitable for USB peripheral power, industrial sensor nodes, set-top box AV subsystems, and laptop docking port logic requiring stable component supply with guaranteed 200 mA output and -40 °C to 125 °C operation.

Supply support for LDK220U50R 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 battery-powered and thermally constrained applications requiring ultra-low-noise, low-quiescent-current LDOs with ceramic capacitor compatibility and robust thermal protection-optimized for space- and efficiency-critical designs.

FAQ

What is the maximum input voltage for LDK220U50R?

The absolute maximum DC input voltage is 14 V, but the recommended operating range is 2.5 V to 13.2 V per the datasheet. Exceeding 13.2 V risks violating safe operating area limits, especially at high junction temperatures. The device includes internal overvoltage clamp protection on the IN pin, but sustained operation above 13.2 V is not characterized or guaranteed.

Can LDK220U50R be used with a 1 µF ceramic output capacitor?

Yes-LDK220U50R is explicitly designed and characterized for stability with 1 µF X5R or X7R ceramic capacitors (ESR < 100 mΩ). Figure 22 in DS10219 confirms the stability region includes C_OUT = 1 µF and ESR down to 0.01 Ω. No series resistor or additional capacitance is required, unlike older LDOs that mandate minimum ESR.

Does LDK220U50R have an enable pin?

No-LDK220U50R in SOT-89 package has no enable (EN) pin. As stated in Table 3 and the "Typical application" section, the enable function and ADJ pin are unavailable in SOT-89 variants. This part operates continuously when powered; shutdown requires removing input voltage or using an external FET switch on the IN rail.

What is the thermal resistance of the SOT-89 package?

The junction-to-ambient thermal resistance (R_thJA) for LDK220U50R in SOT-89 is 110 °C/W under JEDEC JESD51-7 4-layer board conditions. Achieving this value requires proper PCB layout: a minimum 100 mm² copper pour connected to pin 2 (GND) with ≥4 thermal vias (0.3 mm diameter) to inner ground planes. Without thermal enhancement, R_thJA may exceed 200 °C/W.