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LDO40LPU33RY

LDO40LPU33RY

STMicroelectronics
Linear Voltage Regulator IC Positive Fixed 1 Output 400mA 6-DFN (3x3)
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Overview

The LDO40LPU33RY is a high-voltage, low-dropout linear regulator from STMicroelectronics designed for automotive and industrial environments. It delivers a fixed 3.3V output at up to 400mA while tolerating input voltages as high as 38V. This AEC-Q100 qualified device features an exceptionally low typical dropout voltage of 0.27V at full load, making it ideal for maintaining regulation during battery cranking or low-voltage transients.

Why Choose This Part

The regulator offers high reliability with integrated thermal shutdown and current limitation. Its 77dB PSRR at 100Hz effectively filters input ripple, while the wide input range up to 38V handles significant supply spikes. The 3x3mm DFN6 package provides a small footprint with an exposed pad for efficient heat dissipation in high-power applications.

Applications

Automotive ECU Power
Providing stable 3.3V rails for microcontrollers and sensors directly from a 12V or 24V vehicle battery system.
Industrial Automation
Regulating 24V DC industrial control loops down to logic levels for communication interfaces and PLC logic.
Always-On Battery Systems
Leveraging the 45uA typical quiescent current to minimize standby power drain in security and monitoring hardware.

Key Specifications

PSRR 77dB ~ 42dB (100Hz ~ 10kHz)
Output Type Fixed
Mounting Type Surface Mount, Wettable Flank
Package / Case 6-VDFN Exposed Pad
Control Features Enable
Current - Output 400mA
Protection Features Current Limit, Thermal Shutdown
Number of Regulators 1
Output Configuration Positive
Operating Temperature -40degC ~ 125degC (TJ)
Voltage - Input (Max) 38V
Voltage Dropout (Max) 0.27V @ 400mA
Current - Supply (Max) 140 uA
Supplier Device Package 6-DFN (3x3)
Current - Quiescent (Iq) 90 uA
Voltage - Output (Min/Fixed) 3.3V

Getting Started

When designing the PCB, place a 1uF ceramic capacitor close to the input pin and a 2.2uF ceramic capacitor at the output for stability. Ensure the exposed pad is soldered to a copper ground plane to manage the thermal load, especially when dropping 24V or 36V down to 3.3V. For evaluation, ST provides various LDO demonstration boards such as the STEVAL-LDO001V1 for general linear regulator testing.

Also Consider

NCV4264-2 ONonsemi - An AEC-Q100 qualified alternative with a similar 3.3V fixed output and low dropout performance in a SOT-223 package.