STMicroelectronics LDLN025PU50R

Overview

LDLN025PU50R from STMicroelectronics is a 250 mA ultra-low-noise low-dropout (LDO) voltage regulator in DFN4-1x1 package, delivering 5.0 V output with ±2% accuracy across line, load, and temperature. It operates from 1.5 V to 5.5 V input, achieves 250 mV dropout at 250 mA, and features 6.5 μVRMS output noise and 80 dB PSRR at 100 Hz-optimized for powering noise-sensitive RF modules and image sensors in portable electronics.

For engineers reviewing the LDLN025PU50R datasheet, LDLN025PU50R pinout, LDLN025PU50R application, or LDLN025PU50R equivalent, this LDO is selected for battery-powered systems requiring extended standby life (12 μA quiescent current), clean power delivery under dynamic load (±40 mV load transient), logic-controlled shutdown (<1 μA off-state), and stable operation with 1 μF ceramic capacitors.

Technical Context

The LDLN025PU50R implements a bandgap-referenced error amplifier driving a PMOS pass transistor, enabling ultra-low dropout and controlled quiescent current even in dropout condition. Its internal soft-start and output discharge circuitry prevent inrush current and ensure safe power sequencing.

Designed for high-PSRR performance up to 100 kHz and ultra-low noise across 10 Hz–100 kHz bandwidth, it integrates thermal shutdown (160 °C trip, 20 °C hysteresis) and current limiting (250–500 mA short-circuit protection), with EN pin logic thresholds (VIL = 0.4 V, VIH = 1.2 V) compatible with standard CMOS interfaces.

Key Specifications

Pinout & Package

LDLN025PU50R is packaged in DFN4-1x1 (1.0 mm × 1.0 mm × 0.38 mm), thermally enhanced with exposed pad connected to GND. This 4-pin package supports high-density layout and efficient heat dissipation (R_thJA = 220 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B502MR-G and ADP160AUJZ-5.0-R7, LDLN025PU50R uniquely balances 250 mA capability, 6.5 μVRMS noise, integrated output discharge, and DFN4-1x1 size-making it optimal for compact, battery-powered RF and imaging systems demanding both low noise and robust power sequencing.

Availability

LDLN025PU50R is available at Aetrix Electronics and suitable for smartphone RF modules, image sensor biasing, portable instrumentation, and wireless LAN VCO power supplies requiring stable component supply, long-term lifecycle support, and traceable sourcing.

Supply support for LDLN025PU50R 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 specializing in power management, analog, and microcontroller solutions for automotive, industrial, and consumer markets.

The LDLN025 series belongs to ST's ultra-low-noise LDO product line, engineered specifically for powering sensitive RF, imaging, and precision analog circuits in battery-operated portable devices.

FAQ

What is the minimum input voltage required for LDLN025PU50R to regulate 5.0 V output?

The LDLN025PU50R requires VIN ≥ 5.25 V to maintain regulation at full 250 mA load, based on its 250 mV dropout specification. At lighter loads, regulation is sustained down to 5.1 V (100 mV dropout). Input below 5.1 V enters dropout mode, where VOUT drops linearly with VIN; the device remains functional but unregulated.

Can LDLN025PU50R be used with tantalum output capacitors?

No-LDLN025PU50R is optimized for ceramic capacitors only (X7R/X5R, 0.7–10 μF, ESR 5–500 mΩ). Tantalum capacitors exhibit higher ESR and potential instability risks due to aging and voltage coefficient; using them may cause oscillation or degraded transient response per Figure 19 stability region analysis.

Does the exposed pad on the DFN4-1x1 package require solder mask opening?

Yes-the exposed pad must be fully exposed (no solder mask) and connected to a dedicated PCB thermal pad tied to the main GND plane via ≥4 thermal vias (0.3 mm diameter, spaced ≤1 mm apart). This ensures R_thJA remains near 220 °C/W and prevents thermal shutdown under 250 mA continuous load.

How does the output discharge feature behave during fast enable/disable cycling?

When EN transitions low, the 230 Ω internal discharge path activates within 150 µs (per Figure 28/29), discharging VOUT to <100 mV in ~1 ms with 1 μF COUT. During rapid toggling (>10 kHz), residual charge may accumulate; for sub-ms discharge, add an external 100 kΩ bleed resistor between VOUT and GND.