STMicroelectronics LD39115J30R

Overview

LD39115J30R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator with fixed 3.0 V output, 80 mV typical dropout at 100 mA, 20 µA typical quiescent current at no load, and 33 µV_RMS noise (1–100 kHz). It operates from 1.5 V to 5.5 V input and supports logic-controlled shutdown for battery-powered mobile and portable systems.

For engineers reviewing the LD39115J30R datasheet, LD39115J30R pinout, LD39115J30R application, or LD39115J30R equivalent, key selection criteria include dropout performance under light-to-full load, sub-1 µA shutdown current, ±2.0% output accuracy at 25 °C, ceramic capacitor compatibility (1 µF C_OUT), and thermal/short-circuit protection in flip-chip packaging.

Technical Context

The LD39115J30R uses a bandgap reference and internal trimming network to maintain stable 3.0 V output across –40 °C to 125 °C junction temperature. Its enable-controlled NMOS pass transistor enables fast 30 µs turn-on and <1 µA off-mode current, while internal current limiting and thermal shutdown (160 °C trip, 20 °C hysteresis) ensure robust operation.

Supply voltage rejection is 74 dB at 1 kHz and 67 dB at 10 kHz (V_OUT = 1.5 V), rolling off above 10 kHz; noise performance is optimized via internal filtering, achieving 33 µV_RMS over 1–100 kHz with minimal external components.

Key Specifications

Pinout & Package

LD39115J30R uses a flip-chip 4-bump package (0.8 × 0.8 mm, 0.4 mm pitch) with no exposed pad. The compact footprint supports high-density PCB layouts in space-constrained applications such as wearables and smart sensors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B302MR-G and RT9013-30GB, LD39115J30R delivers superior dropout (80 mV vs. ≥150 mV), lower noise (33 µV_RMS vs. ≥50 µV_RMS), and integrated thermal protection - making it optimal for space-constrained, battery-sensitive, and thermally demanding applications where reliability is non-negotiable.

Availability

LD39115J30R is available at Aetrix Electronics and suitable for mobile phone power management, wearable sensor hubs, industrial handheld terminals, and automotive cabin controllers requiring stable component supply across production lifecycles.

Supply support for LD39115J30R 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 products for industrial, automotive, and consumer markets.

The LD39115J series belongs to ST's ultra-low-noise LDO portfolio, engineered specifically for battery-powered portable electronics where minimal dropout, nanoscale quiescent current, and sub-50 µV_RMS noise are essential for signal integrity and energy efficiency.

FAQ

What is the minimum input voltage required for LD39115J30R to regulate 3.0 V output?

The LD39115J30R requires an input voltage ≥3.08 V to maintain regulation at 100 mA load, based on its 80 mV typical dropout voltage. At lighter loads, regulation is sustained down to 3.02 V (20 mV dropout), and the absolute minimum operating input is 1.5 V - though regulation fails below V_OUT + V_DROP.

Can LD39115J30R be used with a 1 µF ceramic output capacitor?

Yes - the LD39115J30R is explicitly designed for stability with 1 µF ceramic capacitors (X5R/X7R, ESR < 2 Ω), as confirmed in Section 3 (Typical Application) and Figure 35 of the datasheet. No additional ESR or bulk capacitance is required.

Does LD39115J30R include thermal protection?

Yes - it integrates thermal shutdown that activates at 160 °C junction temperature with 20 °C hysteresis, plus constant-current short-circuit limiting (200 mA typical), both defined in Tables 3 and 6 of the datasheet. These protections operate independently of external circuitry.

How does the enable pin behave under varying temperature conditions?

The EN pin threshold varies with temperature: logic-high threshold ranges from 0.9 V (min) across –40 °C to +125 °C, and logic-low threshold stays ≤0.4 V. Figure 13 confirms stable enable behavior across the full operating range, with <100 nA input current ensuring minimal GPIO loading.