STMicroelectronics LDQ40PU25RY

Overview

LDQ40PU25RY from STMicroelectronics is an AEC-Q100 Grade 1 qualified 250 mA low-dropout linear regulator delivering a fixed 2.5 V output, with 500 mV typical dropout at full load, ±1.5% output voltage tolerance over -40 °C to 150 °C, and 2 μA typical quiescent current at no load. It integrates Power Good indication, logic-controlled shutdown, thermal shutdown, short-circuit protection, and active output discharge-designed for always-on battery-connected automotive subsystems.

For engineers reviewing the LDQ40PU25RY datasheet, LDQ40PU25RY pinout, LDQ40PU25RY application, or LDQ40PU25RY equivalent, key selection criteria include its automotive-grade DFN2x2 6L wettable flanks package, 3.3–40 V input range, 250 mA guaranteed output, ±0.5% room-temperature accuracy, and integrated PG/EN/ADJ functionality in fixed-voltage configuration.

Technical Context

The LDQ40PU25RY employs a P-channel MOSFET pass element enabling ultra-low dropout and stable operation down to 3.3 V input. Its internal bandgap reference and error amplifier deliver high DC accuracy and tight load/line regulation (±3.0 mV static load regulation, 0.05 %/V line regulation).

It features dual-mode protection: current limiting (350–1000 mA) triggered at 90% VOUT(NOM), and short-circuit limiting (65–250 mA) below 0.4 V output; thermal shutdown activates at 170 °C with 20 °C hysteresis, and the open-drain Power Good pin asserts when VOUT reaches ≥93% of nominal value.

Key Specifications

Pinout & Package

LDQ40PU25RY is housed in a DFN 2x2 mm, 6-lead wettable flanks package (ECOPACK® compliant). The exposed pad (Pin 6) must be soldered to GND for thermal and electrical performance. Pin 1 orientation is marked by a laser-etched 2D code per Figure 28 in DS13774 Rev 6.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar low-noise, automotive-grade LDO applications.

Compared with TLE4275G and NCP114AMX25T2G, LDQ40PU25RY uniquely combines AEC-Q100 Grade 1 compliance, 250 mA output, integrated PG, active discharge, and 2 μA quiescent current in a wettable-flank DFN - making it the only drop-in solution for next-generation automotive domain controllers requiring functional safety-aware power sequencing.

Availability

LDQ40PU25RY is available at Aetrix Electronics and suitable for EV powertrain control units, ADAS camera modules, infotainment head units, and instrument cluster electronics requiring stable component supply with automotive-grade traceability and long-term lifecycle support.

Supply support for LDQ40PU25RY 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 LDQ40 series belongs to ST's automotive-qualified power management portfolio, engineered specifically for always-on, low-power, safety-critical subsystems in modern vehicles - emphasizing precision, robustness, and manufacturability in harsh environments.

FAQ

What is the minimum input voltage required for LDQ40PU25RY to regulate at full 250 mA load?

The minimum input voltage is determined by dropout: 2.5 V + 1.0 V (max dropout at 250 mA) = 3.5 V. However, the device enters UVLO below 2.55 V (rising edge), so reliable startup and regulation require VIN ≥ 3.5 V. At lighter loads, regulation begins as low as 2.65 V due to lower dropout.

Can LDQ40PU25RY be used with ceramic output capacitors less than 1 µF?

No. The datasheet mandates a minimum 1.0 µF ceramic output capacitor (X5R/X7R) for loop stability. Using smaller values risks oscillation or poor transient response. COUT must also maintain ESR between 5 mΩ and 10 Ω across temperature and bias - verified via manufacturer's ESR vs. DC bias curves.

Is the PG pin compatible with 3.3 V logic systems without a level shifter?

Yes. The PG pin is an open-drain output rated for 13 V maximum, and sinks up to 6 mA. When pulled up to 3.3 V via an external resistor (e.g., 10 kΩ), it delivers clean 0 V / Hi-Z states fully compatible with 3.3 V GPIO inputs - no level shifter needed.

Does LDQ40PU25RY support remote voltage sensing?

No. Remote sensing is only available on the adjustable versions (e.g., LDQ40PURY) via the ADJ/VSENSE pin. LDQ40PU25RY is a fixed-output variant where Pin 5 is VOUT and Pin 4 is PG - VSENSE functionality is internally tied to VOUT and not accessible externally.