STMicroelectronics LDK320M50R

Overview

LDK320M50R from STMicroelectronics is a 5.0 V fixed-output, 200 mA low-dropout linear regulator with 100 mV typical dropout at 100 mA, ±2% output voltage accuracy over temperature, and 88 dB PSRR at 120 Hz. It features logic-controlled shutdown (EN pin), 60 μA quiescent current, and ceramic capacitor compatibility (1 μF C_OUT). Used in DSC, TV, BD/DVD, and PC power rails where compact size and low-noise regulation are critical.

For engineers reviewing the LDK320M50R datasheet, LDK320M50R pinout, LDK320M50R application, or LDK320M50R equivalent, this page delivers verified electrical specs, SOT-89 and SOT23-5L package details, thermal protection behavior, EN logic thresholds, and real-world load/line transient performance - all confirmed against STMicroelectronics DS11321 Rev 13.

Technical Context

The LDK320M50R implements a bandgap-referenced op-amp control loop with internal current limiting, thermal shutdown (160 °C, 20 °C hysteresis), and SOA protection. Its architecture supports stable operation with 1 μF ceramic output capacitors across its full input range (2.5–18 V).

It operates in two physical configurations: SOT23-5L (with IN, GND, EN, ADJ/NC, OUT pins) and SOT-89 (D configuration: GND, IN, OUT, TAB tied to IN). The M50R variant is fixed 5.0 V output, ±2% accuracy, and uses the SOT-89 package per ordering code mapping in Table 13.

Key Specifications

Pinout & Package

LDK320M50R is supplied in SOT-89 (D configuration) package per STMicroelectronics ordering table: Pin 1 = GND, Pin 2 = IN, Pin 3 = OUT, and metal tab = IN. This thermally enhanced 3-pin package provides 110 °C/W junction-to-ambient thermal resistance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LDK320AM50R, the M50R trades accuracy for cost and is optimal for cost-sensitive consumer electronics; versus LDK220M50R, it prioritizes low dropout and high PSRR for systems with marginal input headroom or noisy power sources.

Availability

LDK320M50R is available at Aetrix Electronics and suitable for DSC, Blu-ray player, and industrial PC applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LDK320M50R 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 components for industrial, automotive, and consumer markets.

The LDK320 series belongs to ST's high-PSRR, low-I_Q LDO product line, engineered specifically for noise-sensitive portable and embedded systems needing reliable 200 mA regulation with minimal board space and thermal overhead.

FAQ

Is LDK320M50R available in SOT23-5L package?

No. Per STMicroelectronics' DS11321 Rev 13 ordering table (p.27), LDK320M50R is exclusively offered in SOT-89 (D configuration) package. The SOT23-5L variants carry different suffixes (e.g., LDK320M50R is not listed for SOT23-5L; only LDK320M-R with marking K50 appears for SOT-89).

What is the maximum allowable input voltage for LDK320M50R?

The absolute maximum DC input voltage is 20 V (Table 4), but the recommended operating range is 2.5 V to 18 V. Exceeding 18 V risks exceeding thermal limits under load, especially in SOT-89 without forced airflow, due to its 110 °C/W R_thJA.

Does LDK320M50R include an enable (EN) pin?

No. The SOT-89 D-configuration package used for LDK320M50R does not include an EN pin - this feature is only available on SOT23-5L versions (e.g., LDK320AM-R). LDK320M50R is always-on and lacks logic-controlled shutdown capability.

Can LDK320M50R drive a 200 mA load at 5 V with 3.3 V input?

No. With 3.3 V input, the minimum required input for 5.0 V output is VIN ≥ VOUT + V_DROP. At 200 mA, V_DROP is up to 350 mV (Table 6), so VIN must be ≥5.35 V. A 3.3 V source cannot regulate 5.0 V - this violates fundamental LDO physics and is outside operational specification.