STMicroelectronics LD39030ADTPU18R

Overview

LD39030ADTPU18R from STMicroelectronics is a 300 mA ultra-low-dropout linear voltage regulator with 1.8 V fixed output, ±0.5 % accuracy at 25 °C, 300 mV typical dropout at 300 mA, and 20 µA typical quiescent current at no load. It operates from 1.5 V to 5.5 V input and features logic-controlled shutdown, internal soft-start, and optional output discharge - optimized for space-constrained battery-powered systems such as mobile phones and digital still cameras.

For engineers reviewing the LD39030ADTPU18R datasheet, LD39030ADTPU18R pinout, LD39030ADTPU18R application, or LD39030ADTPU18R equivalent, key selection criteria include output accuracy tolerance, dropout behavior under 300 mA load, thermal performance in DFN4 1×1 package, EN pin logic thresholds, and compatibility with 0.47 µF ceramic output capacitors.

Technical Context

The LD39030ADTPU18R implements a PMOS pass transistor architecture enabling ultra-low dropout (330 mV max at 300 mA, −40 °C to 125 °C) and high PSRR (80 dB @ 1 kHz, 55 dB @ 100 kHz). Its internal soft-start circuit limits inrush current without external components, while the integrated output discharge MOSFET (RON = 100 Ω) actively discharges COUT when EN is low.

Stability is guaranteed with ≥0.47 µF X5R/X7R ceramic output capacitors and 1 µF input capacitor; the control loop tolerates ESR down to ~10 mΩ per Figure 17. Thermal protection triggers at 160 °C with 20 °C hysteresis, and RthJA is 250 °C/W in standard PCB layout.

Key Specifications

Pinout & Package

Supplied in STMicroelectronics' DFN4 1×1 mm, 0.4 mm height, thermally enhanced package with exposed thermal pad tied to GND. Pin pitch is 0.65 mm; recommended footprint per Figure 29 (DS11386 Rev 5, p.16).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-dropout linear regulator applications.

Compared with XC6210B182MR-G and RT9013-18GB, the LD39030ADTPU18R delivers tighter output accuracy (±0.5 %), integrated thermal shutdown, and active output discharge - making it uniquely suited for safety-critical, space-constrained, and fast-sequencing portable applications where reliability and board-area savings outweigh minor IQ differences.

Availability

LD39030ADTPU18R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, and cordless phone systems requiring stable component supply, long-term manufacturability, and automotive-grade temperature support (−40 °C to 125 °C).

Supply support for LD39030ADTPU18R 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 LD39030 belongs to ST's high-accuracy, ultra-low-IQ LDO family targeting battery-powered portable electronics - engineered specifically for minimal footprint, robust thermal behavior, and seamless integration with modern low-voltage SoCs and sensors.

FAQ

What is the minimum input voltage required for 1.8 V output regulation at 300 mA load?

The LD39030ADTPU18R requires VIN ≥ VOUT + VDROP = 1.8 V + 0.33 V = 2.13 V to maintain regulation at 300 mA and −40 °C to 125 °C. At 25 °C, typical dropout is 300 mV, so 2.1 V suffices. Below this threshold, output collapses linearly with input.

Does the LD39030ADTPU18R require an external soft-start capacitor?

No. The device integrates a factory-trimmed soft-start circuit that achieves 100 µs typical turn-on time without any external components. Adding an external capacitor is neither required nor recommended, as it may destabilize the internal timing and degrade transient response.

Can the LD39030ADTPU18R be used with a 0.22 µF output capacitor?

No. While the regulator remains stable down to 220 nF under ideal lab conditions, ST specifies 0.47 µF as the minimum for guaranteed stability across temperature, input voltage, and load variations (per Figure 17 and Section 6.3). Using 0.22 µF risks oscillation or poor transient recovery.

Is the thermal pad electrically isolated or must it be connected to GND?

The thermal pad is internally connected to GND and must be soldered to a dedicated PCB GND plane. Leaving it floating or connecting it to another net violates absolute maximum ratings and compromises thermal performance, potentially triggering premature thermal shutdown or parametric shift.