STMicroelectronics LDK320AM50R

Overview

LDK320AM50R from STMicroelectronics is a 5.0 V fixed-output, high-accuracy (±0.5% @ 25 °C), low-dropout linear regulator delivering up to 200 mA with 100 mV typical dropout at 100 mA, 88 dB PSRR at 120 Hz, and 60 μA quiescent current - designed for power-sensitive embedded systems in consumer audio and industrial control.

For engineers reviewing the LDK320AM50R datasheet, LDK320AM50R pinout, LDK320AM50R application, or LDK320AM50R equivalent, this page provides verified electrical behavior, SOT23-5L package mapping, thermal protection details, and design-critical stability guidance for ceramic-capacitor-based 5 V rail generation.

Technical Context

The LDK320AM50R implements a bandgap-referenced op-amp control loop with integrated bias generator and thermal shutdown (160 °C, 20 °C hysteresis). Its enable input (EN) supports logic-level shutdown with sub-1 μA off-state current, and it features internal short-circuit current limiting (330 mA typ.) and SOA protection.

Stable with 1 μF ceramic output capacitors across its full operating range (−40 °C to +125 °C), the device achieves low noise (63 μV_RMS, 10 Hz–100 kHz) and excellent line/load regulation (≤0.05 %/V and ≤15 mV over 1–200 mA), making it suitable for noise-sensitive analog supply domains.

Key Specifications

Pinout & Package

SOT23-5L (5-pin, surface-mount, 1.25 mm max height) with exposed thermal pad connected to GND internally. Pin 4 is NC (not connected) for fixed-output variants like LDK320AM50R.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout, fixed-output voltage regulator applications.

Compared with TLV70750DBVR and MCP1703T-5002E/MB, the LDK320AM50R uniquely combines 200 mA capability, ±0.5% accuracy, EN control, and 100 mV dropout - making it optimal for precision 5 V rails in thermally constrained, battery-aware industrial and consumer systems.

Availability

LDK320AM50R is available at Aetrix Electronics and suitable for digital still cameras, industrial PLC I/O modules, Blu-ray player audio subsystems, and smart home hub microcontroller cores requiring stable component supply across extended temperature and long product lifecycles.

Supply support for LDK320AM50R 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, specializing in power management, microcontrollers, sensors, and automotive ICs with ISO 9001 and IATF 16949 certified manufacturing.

The LDK320 series belongs to ST's high-accuracy, low-noise LDO portfolio targeting battery-powered and noise-sensitive applications - engineered for minimal footprint, robust thermal behavior, and seamless integration with ceramic capacitors.

FAQ

What is the minimum input voltage required for stable 5.0 V output at 200 mA?

The LDK320AM50R requires VIN ≥ VOUT + VDROP. At 200 mA and 25 °C, VDROP is 200–350 mV (typ./max). Thus, minimum VIN is 5.2 V (typ.) or 5.35 V (max). For guaranteed operation across −40 °C to +125 °C, design for VIN ≥ 5.4 V to accommodate worst-case dropout and temperature drift.

Can the LDK320AM50R be used with a 0.47 μF ceramic output capacitor?

No. The datasheet specifies 1–22 μF for stability, with 1 μF as the minimum validated value. Using 0.47 μF risks oscillation due to insufficient phase margin - confirmed by Figure 25 stability plan showing instability below 1 μF at typical ESR values. Always use ≥1 μF X5R/X7R ceramic with ≤100 mΩ ESR.

Is the EN pin compatible with 1.8 V logic microcontrollers?

Yes. The EN pin logic-high threshold is 1.2 V (min) over −40 °C to +125 °C, and logic-low is ≤0.4 V. A 1.8 V GPIO satisfies the high threshold with 0.6 V margin, ensuring reliable activation. Input leakage is ≤100 nA, posing negligible load on the driving MCU pin.

Does the LDK320AM50R require an input capacitor, and if so, what value?

Yes. While not strictly mandatory for stability, ST recommends a 1 μF ceramic input capacitor (X5R/X7R) placed within 3 mm of the IN and GND pins. This reduces high-frequency noise coupling and improves transient response - especially critical when sourced from switchers or long traces. Layout guidelines in DS11321 Rev 13 Section 7.1 confirm this practice.