STMicroelectronics LD39200PU33R

Overview

LD39200PU33R from STMicroelectronics is a fixed-output 3.3 V, 2 A ultra-low-dropout linear regulator with 130 mV typical dropout at full load, 1 % output accuracy at 25 °C, 70 dB PSRR at 1 kHz, and integrated Power Good flag and reverse current protection. It operates from 1.25 V to 6.0 V input and is stable with 10 µF ceramic output capacitors-used in telecom infrastructure point-of-load (POL) supplies where low noise and high PSRR are critical.

For engineers reviewing the LD39200PU33R datasheet, LD39200PU33R pinout, LD39200PU33R application, or LD39200PU33R equivalent, key selection considerations include dropout voltage under 2 A load at low VIN, thermal performance in DFN6 (3 × 3 mm), Power Good threshold behavior (0.92×VOUT rising edge), and compatibility with ceramic capacitor-based POL designs requiring <40 µVRMS noise.

Technical Context

The LD39200PU33R uses a PMOS pass transistor architecture enabling ultra-low dropout and inherent reverse current blocking without external components. Its bandgap-referenced error amplifier drives the pass element with internal RC filtering for stability across 10 µF ceramic output capacitance.

It integrates dual protection: constant-current short-circuit limiting (3.5 A typ.) and thermal shutdown at 170 °C with 20 °C hysteresis, plus an open-drain Power Good output that asserts high-impedance only when VOUT remains within ±8 % of nominal (0.92× to 0.80×VOUT).

Key Specifications

Pinout & Package

LD39200PU33R is packaged in a thermally enhanced DFN6 (3 × 3 mm) with exposed pad, optimized for PCB heat dissipation (R_THJA = 55 °C/W). Pin numbering follows top-view orientation per DS10079 Rev 3.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar LDO regulator applications.

Compared with TPS7A4700RGWR and ADP1740ACPZ-3.3-R7, the LD39200PU33R uniquely combines ultra-low dropout, integrated Power Good, reverse current protection, and DFN6 thermal efficiency-making it optimal for space-constrained, safety-aware POL designs where supply integrity and sequencing matter.

Availability

LD39200PU33R is available at Aetrix Electronics and suitable for telecom infrastructure, industrial FPGA power, medical imaging sensor interfaces, and automotive infotainment systems requiring stable component supply with guaranteed 2 A output and extended temperature support.

Supply support for LD39200PU33R 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 specializing in power management, analog, microcontrollers, and automotive-grade ICs, with manufacturing aligned to ISO 9001 and AEC-Q200 standards.

The LD39200 series belongs to ST's high-performance LDO portfolio, engineered for demanding point-of-load applications in telecom, industrial, and medical equipment where low dropout, high PSRR, and robust protection are mandatory.

FAQ

What is the minimum input voltage required for stable 3.3 V output at 2 A?

The LD39200PU33R requires VIN ≥ 3.43 V (3.3 V + 130 mV dropout) for full 2 A output at room temperature; derating applies above 85 °C due to increased dropout. At –40 °C, dropout drops to ~110 mV, allowing VIN as low as 3.41 V. Input below 1.25 V is not supported per absolute maximum ratings.

How should the ADJ/SENSE pin be connected on this fixed 3.3 V version?

On the LD39200PU33R (fixed-output variant), the ADJ/SENSE pin (Pin 2) must be directly shorted to the OUT pin (Pin 1) using a low-inductance PCB trace. This connection ensures accurate output regulation and correct Power Good assertion; leaving it floating or connecting to ground will cause regulation failure and PG malfunction.

Does the LD39200PU33R require an input capacitor, and what value is recommended?

Yes-an input capacitor is mandatory for stability and EMI reduction. ST recommends ≥10 µF X5R/X7R ceramic capacitor placed as close as possible to the IN and GND pins. A 22 µF capacitor further improves line transient response. The capacitor must have low ESR (<100 mΩ) and be rated for ≥6.3 V DC.

Can the Power Good (PG) pin drive a microcontroller GPIO directly?

Yes-the PG pin is an open-drain output rated for 6 mA sink current and 7 V max voltage. It can directly interface with 3.3 V or 5 V microcontroller GPIOs configured as pull-up inputs. No level-shifting is needed; a 10 kΩ external pull-up to the MCU's VDD is sufficient to generate a clean logic-high signal when VOUT is in regulation.