STMicroelectronics LD39015J18R

Overview

LD39015J18R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator delivering a fixed 1.8 V output with ±2.0% accuracy at 25 °C, 90 mV typical dropout at 100 mA, 54 µV_RMS output noise (10 Hz–100 kHz), and logic-controlled shutdown consuming ≤1 µA in off mode - deployed in battery-powered mobile and portable electronics requiring stable, clean power rails.

For engineers reviewing the LD39015J18R datasheet, LD39015J18R pinout, LD39015J18R application, or LD39015J18R equivalent, key selection criteria include dropout voltage under load, quiescent current across temperature, ceramic capacitor compatibility (1 µF min), enable logic thresholds, and thermal protection behavior in compact flip-chip packages.

Technical Context

The LD39015J18R employs a bandgap reference and internal trimming to maintain tight output voltage accuracy across -40 °C to 125 °C junction temperature. Its flip-chip architecture minimizes parasitic inductance, supporting fast transient response and stability with low-ESR ceramic capacitors.

Enable control uses TTL-compatible logic levels (V_IL ≤ 0.4 V, V_IH ≥ 0.9 V) to switch between active regulation and sub-1 µA shutdown. Internal current limiting (200 mA typ.) and thermal shutdown (160 °C, 20 °C hysteresis) provide robust fault protection without external components.

Key Specifications

Pinout & Package

LD39015J18R is housed in a Flip-chip 4-bump package measuring 1.1 × 1.1 mm with 0.4 mm pitch, optimized for space-constrained PCB layouts and high thermal conductivity via direct die attachment.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6219B182MR-G and RT9013-18GB, the LD39015J18R delivers superior noise performance and smallest footprint, making it optimal for space- and noise-sensitive battery-powered designs where 150 mA is sufficient.

Availability

LD39015J18R is available at Aetrix Electronics and suitable for wearable health monitors, Bluetooth LE sensor nodes, and industrial handheld scanners requiring stable component supply, consistent parametric performance, and long-term lifecycle support.

Supply support for LD39015J18R 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 LD39015J series targets ultra-low-power portable electronics, emphasizing minimal quiescent current, low noise, and small-footprint packaging for next-generation battery-operated devices.

FAQ

What is the minimum input voltage required for regulation at full 150 mA load?

The LD39015J18R requires VIN ≥ VOUT + VDROP = 1.8 V + 0.13 V = 1.93 V (max dropout at 125 °C) to maintain regulation at 150 mA. At room temperature, 1.89 V input suffices due to 90 mV typical dropout. Below 1.45 V, UVLO disables regulation entirely.

Can the LD39015J18R operate with a 1 µF X5R ceramic capacitor on the output?

Yes - the device is explicitly characterized and stable with 1 µF ceramic capacitors (X5R, X7R) having ESR ≤ 3 Ω. The datasheet's Figure 7 defines the stable COUT–ESR region, confirming 1 µF is within specification for all load conditions from 1 mA to 150 mA.

How does the enable pin behave during power-up sequencing?

The EN pin has TTL-compatible thresholds: regulation begins when EN rises above 0.9 V (typ.), with 30 µs typical turn-on time to 95% of 1.8 V. If EN is left floating, internal pull-down ensures default shutdown; no external pull-up is required for safe power-up.

Is thermal derating required for continuous 150 mA operation in still air?

Yes - with R_thJA = 180 °C/W, dissipating 150 mA × (VIN − 1.8 V) can exceed 125 °C junction temperature. At VIN = 3.3 V, power dissipation is 225 mW, raising junction temperature by 40.5 °C above ambient. Keep ambient ≤ 85 °C or add copper pour for thermal relief.