STMicroelectronics LD39150PT25-R

Overview

LD39150PT25-R from STMicroelectronics is a fixed-output 2.5 V, 1.5 A ultra-low-dropout linear regulator in DFN6 (3×3 mm) package, fabricated on BiCMOS process. It delivers 200 mV typical dropout at full load, 1 mA typical quiescent current during operation, and supports -40 to 125 °C junction temperature range. Designed for microprocessor core power supply with fast transient response and ceramic-capacitor stability.

For engineers reviewing the LD39150PT25-R datasheet, LD39150PT25-R pinout, LD39150PT25-R application, or LD39150PT25-R equivalent, key selection criteria include guaranteed 1.5 A output, ±1.5% output voltage tolerance at 25 °C, logic-controlled inhibit function, thermal/current protection, and compatibility with low-ESR ceramic output capacitors ≥2.2 µF.

Technical Context

The LD39150PT25-R implements a BiCMOS-based error amplifier and pass transistor architecture enabling ultra-low quiescent current independent of load-1 µA max in shutdown and 1 mA typ. at 1.5 A output. Its internal reference is trimmed to 1.22 V, supporting fixed 2.5 V output via resistor feedback network embedded in die.

It features active current limiting (3 A short-circuit protection), thermal shutdown at 170 °C with 10 °C hysteresis, and fast line/load transient response due to high gain-bandwidth error amplifier. The inhibit input (VINH) requires external pull-up or driver-no internal bias-and transitions between ON (≥2 V) and OFF (≤0.3 V) modes.

Key Specifications

Pinout & Package

LD39150PT25-R uses the DFN6 (3 × 3 mm) package with exposed thermal pad (TAB) electrically connected to GND. The 6-pin layout supports compact layout and efficient thermal dissipation when soldered to PCB ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPS7A4700RGWR and ADP1740ACPZ-2.5-R7, LD39150PT25-R uniquely balances 1.5 A capability, 200 mV dropout, 1 µA shutdown, and ceramic-stability in DFN6-making it optimal for space-constrained, high-current embedded processors.

Availability

LD39150PT25-R is available at Aetrix Electronics and suitable for microprocessor core supply, DSP power rail, and industrial sensor node applications requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LD39150PT25-R 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and quality certifications.

LD39150 belongs to ST's ultra-low-dropout linear regulator product line, engineered specifically for high-efficiency, low-noise power delivery in battery-powered and thermally constrained embedded systems.

FAQ

What is the minimum output capacitor value required for stability?

The LD39150PT25-R requires a minimum 2.2 µF ceramic output capacitor with ESR ≤100 mΩ for guaranteed stability across temperature and load. Lower ESR values are acceptable, but capacitance must remain ≥2.2 µF; using smaller values risks oscillation, especially under light load or high ambient temperature.

Can the inhibit pin be left unconnected?

No-the VINH pin has no internal pull-up or pull-down and must never be left floating. To maintain continuous operation, connect VINH directly to VI. To enable shutdown, drive VINH ≤0.3 V with an open-drain or push-pull signal referenced to GND.

Is the DFN6 package thermally adequate for 1.5 A continuous operation?

Yes-the DFN6 (3×3 mm) package achieves R_thJA = 40 °C/W with a PCB ground plane heatsink. At 1.5 A and 200 mV dropout (0.3 W dissipation), junction temperature rise is ~12 °C above ambient-well within the -40 to 125 °C operating range, provided copper area meets ST's recommended footprint.

Does LD39150PT25-R support reverse current blocking?

Yes-it integrates body-diode reverse-current blocking. When VI falls below VO (e.g., during input brownout), the pass transistor prevents backflow from VO to VI, protecting upstream sources and avoiding unintended power rail coupling in multi-rail systems.