STMicroelectronics LD39020ADTPU18R

Overview

LD39020ADTPU18R from STMicroelectronics is a 200 mA ultra-low-dropout linear voltage regulator with 1.8 V fixed output, ±0.5 % accuracy at 25 °C, 200 mV typical dropout at 200 mA, and 20 µA typical quiescent current. It features logic-controlled enable, internal soft-start, optional output discharge MOSFET, and operates from 1.5 V to 5.5 V input - designed for precision power rails in battery-powered imaging and mobile SoC subsystems.

For engineers reviewing the LD39020ADTPU18R datasheet, LD39020ADTPU18R pinout, LD39020ADTPU18R application, or LD39020ADTPU18R equivalent, key selection criteria include output accuracy tolerance, shutdown current (<0.1 µA), ceramic capacitor compatibility (≥0.47 µF), thermal performance in DFN4 1x1 package, and auto-discharge functionality for fast rail collapse in portable media systems.

Technical Context

The LD39020ADTPU18R integrates a bandgap reference, error amplifier, and PMOS pass transistor in a fully regulated feedback loop. Its internal soft-start limits inrush current by controlling output ramp-up over ~100 µs without external components.

It includes an enable-controlled NMOS discharge switch (RON ≈ 100 Ω) tied to the EN pin, activated during shutdown to rapidly deplete output capacitance. Thermal protection triggers at 160 °C with 20 °C hysteresis, and PSRR reaches 80 dB at 1 kHz and 55 dB at 100 kHz under 30 mA load.

Key Specifications

Pinout & Package

LD39020ADTPU18R is packaged in DFN4 1x1 (1.0 mm × 1.0 mm, 0.4 mm height), featuring wettable flanks and a thermal pad connected to GND for enhanced heat dissipation in space-constrained layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD39020ADTPU18R, both alternatives offer lower cost but sacrifice ±0.5 % accuracy, integrated discharge, and DFN4 1x1 space efficiency - making them suitable only where tighter regulation and rapid power-down are non-critical.

Availability

LD39020ADTPU18R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and portable media players requiring stable component supply, long-term lifecycle support, and AEC-Q200-aligned reliability in compact form factors.

Supply support for LD39020ADTPU18R 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, specializing in power management, microcontrollers, and analog ICs for automotive, industrial, and consumer markets.

The LD39020 series belongs to ST's ultra-low-I_Q LDO portfolio, engineered specifically for battery-powered portable electronics demanding sub-1 µA shutdown current, fast enable response, and minimal PCB footprint.

FAQ

What is the minimum output capacitor value required for stable operation?

The LD39020ADTPU18R is stable with a minimum 0.47 µF X5R or X7R ceramic capacitor on the output. This value ensures phase margin >45° across −40 °C to +125 °C and full load range. Using smaller capacitors (e.g., 220 nF) may cause oscillation under temperature or load variation, so 0.47 µF is the recommended design minimum.

Does the LD39020ADTPU18R require an input capacitor, and if so, what type and value?

Yes - a minimum 1 µF X5R or X7R ceramic capacitor is required on the IN pin, placed within 2 mm of the device. This capacitor filters high-frequency noise from upstream sources and maintains loop stability during line transients. Larger values (e.g., 2.2 µF) improve ripple rejection but are not mandatory for basic operation.

How does the output discharge feature operate, and when is it active?

The output discharge MOSFET activates automatically when the EN pin is driven low, connecting VOUT to GND via a ~100 Ω channel. It discharges a 1 µF output capacitor to <100 mV in under 1 ms. This function is enabled only on "D" suffix variants like LD39020ADTPU18R and remains inactive during normal regulation.

Can LD39020ADTPU18R be used with input voltages below 1.8 V?

No - although the absolute minimum input rating is 1.5 V, regulation cannot be maintained below V_OUT + V_DROP. At 200 mA load, dropout is 200–350 mV, so functional input range starts at ~2.0 V. Below that, output collapses linearly; for sub-2.0 V operation, consider a 1.2 V or 1.5 V variant from the same family.