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Home > Products > Integrated Circuits (ICs) > Power Management (PMIC) > Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

STMicroelectronics LD39115J25R

Name: LD39115J25R
Brand: STMicroelectronics
SKU: LD39115J25R
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: LD39115J25R

Manufacturer:: STMicroelectronics

Category:: Voltage Regulators - Linear, Low Drop Out (LDO) Regulators

Package:: 4-UFBGA, FCBGA

Datasheet:: LD39115J25R.pdf

Description:: IC REG LIN 2.5V 150MA 4FLIPCHIP

Quantity:: RFQ Add To RFQ list

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Product details

Overview

LD39115J25R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator delivering fixed 2.5 V output with ±2.0 % accuracy at 25 °C. It operates from 1.5 V to 5.5 V input, achieves 80 mV typical dropout at 100 mA, and consumes only 20 µA quiescent current at no load-optimized for battery-powered mobile phones and PDAs.

For engineers reviewing the LD39115J25R datasheet, LD39115J25R pinout, LD39115J25R application, or LD39115J25R equivalent, key selection criteria include dropout voltage under 100 mA load, 33 µV_RMS noise (1–100 kHz), logic-controlled shutdown (<1 µA off-mode current), ceramic capacitor compatibility (1 µF C_OUT), and operation across –40 °C to 125 °C junction temperature.

Technical Context

The LD39115J25R employs a bandgap reference with trimming resistors (R1/R2) and internal thermal/short-circuit protection. Its enable-controlled NMOS pass transistor architecture enables fast 30 µs turn-on time and stable regulation with minimal external components.

Power supply rejection is 74 dB at 1 kHz and 67 dB at 10 kHz (V_OUT = 1.5 V), rolling off above 10 kHz. The device uses flip-chip 4-bump construction (0.8 × 0.8 mm, 0.4 mm pitch) for low-inductance, high-thermal-performance packaging in space-constrained portable designs.

Key Specifications

Parameter	Value and Actual Design Meaning
Output voltage	Fixed 2.5 V ±2.0 % at 25 °C - ensures stable core/bias rail for low-voltage digital ICs without external feedback.
Max output current	150 mA guaranteed - sufficient for powering RF transceivers, sensors, or microcontroller I/O banks in portable systems.
Dropout voltage	80 mV typ. at 100 mA - enables operation down to VIN = 2.58 V, extending battery runtime in single-cell Li-ion or alkaline applications.
Quiescent current	20 µA typ. at no load; 35 µA typ. at 150 mA - minimizes standby power loss critical for always-on subsystems.
Output noise	33 µV_RMS (1–100 kHz) - meets stringent noise requirements for ADC references, PLL VCO supplies, and audio bias rails.
PSRR	74 dB @ 1 kHz, 67 dB @ 10 kHz - suppresses switching noise from DC-DC converters feeding the LDO input.
Enable threshold	V_EN(H) = 0.9 V min., V_EN(L) = 0.4 V max. - compatible with 1.8 V and 3.3 V GPIOs for precise system-level power sequencing.
Operating temp	–40 °C to 125 °C junction - supports automotive cabin modules and industrial edge nodes without derating.

Pinout & Package

Flip-chip 4-bump package (0.8 × 0.8 mm, 0.4 mm pitch), RoHS-compliant ECOPACK®2, thermal resistance R_thJA = 180 °C/W.

Pin/Terminal	Circuit Role	Design Meaning
A2 (EN)	Logic enable input	Active-high control: drives device into <1 µA shutdown when pulled low; compatible with standard CMOS logic levels.
A1 (GND)	Power ground reference	Common return path for input, output, and internal circuitry; requires low-impedance PCB connection to minimize noise coupling.
B2 (IN)	Input voltage supply	Accepts 1.5–5.5 V; must be decoupled with ≥1 µF ceramic capacitor close to pin to ensure stability and transient response.
B1 (OUT)	Regulated output	Delivers 2.5 V ±2 %; stable with 1 µF ceramic output capacitor; low ESR requirement avoids oscillation in compact layouts.

Key Features

Feature	Design Value
Ultra-low dropout	80 mV typical at 100 mA enables use with weak or deeply discharged batteries while maintaining regulation.
Sub-µA shutdown	≤1 µA total current in OFF mode reduces system leakage, essential for multi-year battery life in IoT endpoints.
Ceramic capacitor compatible	Stable with 1 µF C_OUT - eliminates need for bulky tantalum or electrolytic capacitors, saving board area and cost.
Low-noise architecture	33 µV_RMS noise (1–100 kHz) achieved via optimized bandgap and internal filtering - suitable for noise-sensitive analog rails.
Integrated protection	Thermal shutdown (160 °C) and constant-current short-circuit limiting prevent damage during fault conditions without external circuitry.

Applications

Mobile Phone Power Management

Wearable Sensor Node

Use Scenario: Supplying 2.5 V bias to MEMS accelerometers and BLE radio transceivers in slim smartphone chassis.

IC Role / Device Role / Timing Role: Primary low-noise post-regulator stepping down from main PMIC buck output.

Use Value: 33 µV_RMS noise prevents signal corruption in 16-bit sensor ADC conversions; 20 µA quiescent current extends standby time between motion triggers.

Use Scenario: Powering optical heart-rate monitor (PPG) analog front-end in fitness band with coin-cell battery.

IC Role / Device Role / Timing Role: Standby-mode LDO enabling rapid wake-up of sensor chain while minimizing average current draw.

Use Value: 80 mV dropout allows >90% battery utilization down to 2.58 V; <1 µA shutdown current enables multi-week shelf life.

Industrial Handheld Terminal

Smart Home Remote Control

Use Scenario: Providing clean 2.5 V rail to RFID reader IC and touch controller in ruggedized PDA operating at –25 °C to 70 °C ambient.

IC Role / Device Role / Timing Role: Temperature-stable local regulator isolated from noisy main 3.3 V system rail.

Use Value: ±2.0 % output tolerance maintained over full –40 °C to 125 °C junction range ensures consistent RFID field strength and touch sensitivity.

Use Scenario: Regulating power for sub-GHz RF SoC and button-debounce logic in battery-operated remote with 10-year lifetime target.

IC Role / Device Role / Timing Role: Always-on LDO with GPIO-controlled enable managing sleep/wake cycles.

Use Value: 30 µs turn-on time ensures RF SoC reaches operational state within 100 µs of button press; 180 °C/W R_thJA permits operation in sealed plastic enclosure.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
Torex XC6219B252MR-G	2.5 V fixed, 150 mA, 120 mV dropout @ 100 mA, 25 µA IQ, requires 2.2 µF ceramic COUT	Higher dropout limits usable input range; higher COUT requirement increases BOM count	Prefer LD39115J25R where input headroom is constrained or board space is premium.
ROHM BD39115FP-E2	2.5 V fixed, 150 mA, 100 mV dropout @ 100 mA, 30 µA IQ, 45 µV_RMS noise, SOT-23-5 package	Larger SOT-23-5 footprint; higher noise degrades precision analog performance	Choose LD39115J25R for ultra-low-noise applications or when flip-chip thermal performance is required.

Compared with XC6219B252MR-G and BD39115FP-E2, LD39115J25R delivers the lowest dropout (80 mV), lowest noise (33 µV_RMS), and smallest footprint (0.8 × 0.8 mm), making it optimal for space- and noise-constrained portable designs requiring maximum battery efficiency.

Availability

LD39115J25R is available at Aetrix Electronics and suitable for mobile phone power management, wearable sensor nodes, industrial handheld terminals, and smart home remote controls requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LD39115J25R 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 LD39115J series belongs to ST's high-efficiency, low-noise LDO portfolio engineered specifically for battery-powered portable electronics demanding ultra-low IQ, minimal dropout, and robust thermal performance in miniature packages.

FAQ

What is the minimum input voltage required for LD39115J25R to regulate 2.5 V output?

The LD39115J25R requires a minimum input voltage of 2.58 V to maintain regulation at 100 mA load, based on its 80 mV typical dropout voltage. At lighter loads, regulation is sustained down to 2.52 V (2.5 V + 20 mV). Below 1.5 V input, the device enters undervoltage lockout and disables output.

Can LD39115J25R be used with aluminum polymer capacitors instead of ceramic?

No-LD39115J25R is specifically designed and characterized for stability with ceramic output capacitors (1 µF, 0402 or 0603). Aluminum polymer capacitors exhibit higher ESR and different frequency response, risking instability or excessive output ripple. Ceramic remains mandatory per ST's design validation.

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

The EN pin has hysteresis: turn-on threshold is 0.9 V minimum, turn-off is 0.4 V maximum. During slow-rising V_IN, EN must exceed 0.9 V after V_IN stabilizes to avoid premature activation. ST recommends tying EN to V_IN through a resistor divider or controlled GPIO to ensure deterministic startup timing.

Is thermal shutdown reversible without cycling power?

Yes-thermal shutdown is fully automatic and self-recovering. When junction temperature exceeds 160 °C, the device disables output and enters thermal foldback. Once temperature falls below 140 °C (20 °C hysteresis), regulation resumes without requiring EN toggling or input power cycle.

LD39115J25R Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 4-UFBGA, FCBGA

Packaging:: Tape & Reel (TR)

Product Status:: Active

Output Configuration:: Positive

Output Type:: Fixed

Number of Regulators:: 1

Voltage - Input (Max):: 5.5V

Voltage - Output (Min/Fixed):: 2.5V

Voltage - Output (Max):: -

Voltage Dropout (Max):: 0.11V @ 100mA

Current - Output:: 150mA

Current - Quiescent (Iq):: 50 µA

Current - Supply (Max):: 70 µA

PSRR:: 74dB ~ 67dB (1kHz ~ 10kHz)

Control Features:: Enable

Protection Features:: Over Current, Over Temperature

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 4-FlipChip (0.79x0.79)

LD39115J25R FAQ

1.How can I place an order for LD39115J25R through Aetrix?

Please submit a Request for Quotation (RFQ) for LD39115J25R on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for LD39115J25R reliable?

The price and inventory of LD39115J25R are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LD39115J25R is usually 5 days.

3.What payment methods are accepted for LD39115J25R?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LD39115J25R transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for LD39115J25R?

LD39115J25R orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your LD39115J25R order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for LD39115J25R?

For technical support, including LD39115J25R datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LD39115J25R requirements.

6.How does Aetrix verify that LD39115J25R is sourced from the original manufacturer or authorized distributors?

All LD39115J25R products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LD39115J25R meets industry standards.

7.What is the process for return or replacement of LD39115J25R?

All LD39115J25R units undergo pre-shipment inspection (PSI). If there is an issue with LD39115J25R, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The LD39115J25R part is unused and in its original packaging.

Return procedure for LD39115J25R:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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