STMicroelectronics LD39115J12R

Overview

LD39115J12R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator delivering a fixed 1.2 V output. It operates from 1.5 V to 5.5 V input, features 80 mV typical dropout at 100 mA, 20 µA typical quiescent current at no load, 33 µV_RMS noise (1–100 kHz), and ±2.0% output accuracy at 25 °C - optimized for power-sensitive portable electronics.

For engineers reviewing the LD39115J12R datasheet, LD39115J12R pinout, LD39115J12R application, or LD39115J12R equivalent, key selection criteria include dropout performance under light/heavy load, shutdown current (<1 µA), ceramic capacitor compatibility (1 µF), thermal/short-circuit protection, and operation across –40 °C to 125 °C junction temperature.

Technical Context

The LD39115J12R uses a bandgap-referenced error amplifier with internal trimming to maintain 1.2 V output within ±2.0% at 25 °C and ±3.0% over full temperature range. Its flip-chip 4-bump construction enables compact 0.8 × 0.8 mm footprint and low thermal resistance (R_thJA = 180 °C/W).

Enable control is logic-compatible: EN < 0.4 V disables the regulator (I_Q < 1 µA), while EN > 0.9 V activates it with 30 µs turn-on time. Internal protections include constant-current short-circuit limiting (~200 mA) and thermal shutdown at 160 °C with 20 °C hysteresis.

Key Specifications

Pinout & Package

LD39115J12R uses a flip-chip 4-bump package (0.8 × 0.8 mm, 0.4 mm pitch), with no external leads - mounting relies on solder bumps A1, A2, B1, B2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LD39115J12R, the XC6210B122MR-G trades lower noise and tighter dropout for higher C_OUT requirement, while the RT9013-12GB offers more current headroom at the cost of noise, efficiency, and quiescent performance - making LD39115J12R optimal for ultra-low-power, noise-sensitive 150 mA applications.

Availability

LD39115J12R is available at Aetrix Electronics and suitable for mobile phones, wearable sensors, industrial handheld terminals, and smart home remotes requiring stable component supply across automotive-grade temperature ranges and long production lifecycles.

Supply support for LD39115J12R 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 components for industrial, automotive, and consumer markets.

The LD39115J series belongs to ST's high-performance LDO portfolio, engineered specifically for ultra-low-power, low-noise battery-powered systems where dropout, quiescent current, and noise floor are critical design constraints.

FAQ

What is the minimum input voltage required for LD39115J12R to regulate 1.2 V?

The LD39115J12R requires a minimum input voltage of 1.5 V per datasheet absolute ratings. At 100 mA load, its typical dropout is 80 mV - meaning VIN must be ≥1.28 V to sustain regulation. However, the 1.5 V minimum ensures reliable startup, line transient immunity, and operation across temperature and process variation.

Can LD39115J12R be used with a 1 µF ceramic capacitor only on the output?

Yes - the LD39115J12R is explicitly designed and characterized for stability with a single 1 µF X5R or X7R ceramic capacitor on the output (no input capacitor required). This is confirmed in Section 3 ("Typical application") and Table 5 of the datasheet, eliminating ESR dependency and simplifying PCB layout.

How does the enable pin behave under varying temperature?

The enable threshold is specified as 0.4 V (max) for logic low and 0.9 V (min) for logic high across –40 °C to 125 °C. Figure 13 shows V_EN(H) remains >0.9 V and V_EN(L) stays <0.4 V over full temperature range, ensuring robust enable/disable functionality without external level-shifting.

Is LD39115J12R RoHS and REACH compliant?

Yes - LD39115J12R is manufactured in STMicroelectronics' ECOPACK2-compliant facilities. Per DocID15527 Rev 8, it meets RoHS Directive 2011/65/EU and REACH Regulation (EC) No. 1907/2006, with lead-free matte tin termination and halogen-free packaging.