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LDQ40PU50R

LDQ40PU50R

STMicroelectronics
Linear Voltage Regulator IC Positive Fixed 1 Output 250mA 6-DFN (2x2)
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Overview

The LDQ40PU50R is a high-voltage, ultra-low quiescent current linear regulator designed for automotive and industrial applications. It delivers a fixed 5V output at 250mA from an input voltage up to 40V, while consuming only 2uA of typical quiescent current. AEC-Q100 Grade 1 qualification makes it suitable for 'always-on' subsystems in harsh environments.

Why Choose This Part

This regulator offers an exceptional balance of a high 40V input rating and ultra-low 2uA typical Iq, which helps extend battery life in standby modes. It features a Power Good output for system sequencing and an active discharge function that quickly clears the output capacitor when the device is disabled. The 2x2mm DFN package provides a compact footprint with high thermal performance for space-constrained designs.

Applications

Automotive Always-On Systems
Ideal for powering keyless entry receivers and security sensors directly from a 12V or 24V battery with minimal drain.
Industrial Sensor Nodes
Provides stable 5V power for remote monitoring equipment connected to 24V industrial supply rails.
EV Battery Management Systems
Used in BMS monitoring circuits where low power consumption and high input voltage tolerance are critical for efficiency.
Smart Metering
Acts as a primary or secondary regulator in utility meters that require long-term reliability and low standby current.

Key Specifications

PSRR 55dB (1kHz)
Output Type Fixed
Mounting Type Surface Mount
Package / Case 6-WDFN Exposed Pad
Control Features Enable
Current - Output 250mA
Protection Features Over Current, Over Temperature, Short Circuit
Number of Regulators 1
Output Configuration Positive
Operating Temperature -40degC ~ 150degC (TJ)
Voltage - Input (Max) 40V
Voltage Dropout (Max) 1V @ 250mA
Current - Supply (Max) 90 uA
Supplier Device Package 6-DFN (2x2)
Current - Quiescent (Iq) 5 uA
Voltage - Output (Min/Fixed) 5V

Getting Started

Designers should place a minimum 1uF ceramic capacitor at the output for stability, ensuring the ESR is within the recommended range. The Power Good pin can be tied to a microcontroller GPIO to monitor the regulation status. For thermal management, ensure the DFN exposed pad is soldered to a PCB ground plane to dissipate heat during high-dropout operation.