STMicroelectronics LDLN050PU33RY

Overview

LDLN050PU33RY from STMicroelectronics is a 500 mA, fixed 3.3 V output low-dropout linear regulator in DFN8 (3 × 3 mm) package, featuring 13 µV_RMS/V_OUT output noise, 190 mV dropout at full load, and 48 µA typical quiescent current. It powers noise-sensitive circuits including wireless transceivers, industrial sensors, and microcontrollers in harsh ambient conditions up to +125 °C.

For engineers reviewing the LDLN050PU33RY datasheet, LDLN050PU33RY pinout, LDLN050PU33RY application, or LDLN050PU33RY equivalent, key selection criteria include ultra-low noise performance with CNR pin support, industrial-grade thermal robustness (–40 °C to +125 °C), fast 50 µs startup, and compatibility with low-ESR ceramic capacitors ≥2 µF.

Technical Context

The LDLN050PU33RY implements a PMOS pass element architecture enabling fast turn-on and low dropout, with integrated UVLO (2.2 V threshold) and thermal shutdown (165 °C). Its feedback loop is internally configured for fixed 3.3 V output, and the NR pin accepts an external capacitor to further suppress output noise.

It features dual protection schemes-current limiting (800 mA typ.) and thermal foldback-and operates without internal pull-up on the EN pin, requiring explicit logic-level control. The device maintains ±2% output accuracy across 1–500 mA load and –40 °C to +125 °C ambient, with PSRR of 65 dB at 100 Hz.

Key Specifications

Pinout & Package

LDLN050PU33RY is housed in a thermally enhanced DFN8 (3 × 3 mm, 0.85 mm height) package with exposed thermal pad. The package complies with JEDEC 2S2P (4L) standards and requires the exposed pad to be soldered to a GND plane for optimal thermal performance (R_thJA = 51 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G, LDLN050PU33RY delivers 500 mA with superior noise suppression via NR pin; versus ADM7172ACPZ-3.3-R7, it offers lower I_Q and smaller DFN8 footprint at the expense of peak current headroom.

Availability

LDLN050PU33RY is available at Aetrix Electronics and suitable for industrial automation, medical point-of-care devices, and wireless sensor networks requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LDLN050PU33RY 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 power management applications.

The LDLN050 series belongs to ST's high-performance LDO portfolio targeting noise-critical industrial and wireless systems, emphasizing ultra-low noise, fast transient response, and extended temperature resilience.

FAQ

What is the minimum input voltage required for LDLN050PU33RY to regulate at full 500 mA load?

The minimum input voltage is 3.49 V - calculated as V_OUT + V_DO = 3.3 V + 190 mV. This ensures guaranteed 500 mA output current across temperature and process variation. Below this, current limit activates before dropout occurs. Input must also exceed 2.7 V per absolute rating.

Can the NR pin be left unconnected, and what is its impact on noise performance?

Yes, the NR pin may be left floating or tied to GND, but doing so forfeits the noise-reduction benefit: output noise rises from 13 µV_RMS/V_OUT to 25 µV_RMS/V_OUT (BW = 10 Hz–100 kHz). For noise-sensitive applications, a 10 nF capacitor between NR and GND is recommended to achieve specified low-noise performance.

Is an external pull-up resistor required on the EN pin?

No - the EN pin has no internal pull-up and must not be left floating. If active-high enable is not used, connect EN directly to GND to force shutdown, or use an external pull-down resistor (≤100 kΩ) to ensure reliable low-state during power-up sequencing and avoid undefined behavior.

Does LDLN050PU33RY require a minimum load current to maintain regulation stability?

No - the device is stable down to zero load current. Stability is ensured with ≥2 µF ceramic output capacitance (ESR < 10 mΩ) and does not require a minimum load. This enables use in intermittent-load applications such as wake-on-event sensor systems without compromising output regulation.