STMicroelectronics LDLN025M28R

Overview

LDLN025M28R from STMicroelectronics is a 250 mA ultra-low-noise low-dropout regulator in SOT23-5L package, delivering 2.8 V output with ±2% accuracy across -40 °C to +125 °C, 6.5 μVRMS noise (10 Hz–100 kHz), 250 mV dropout at 250 mA, and 80 dB PSRR at 100 Hz. It powers noise-sensitive RF and imaging circuits in space-constrained portable devices.

For engineers reviewing the LDLN025M28R datasheet, LDLN025M28R pinout, LDLN025M28R application, or LDLN025M28R equivalent, this page delivers verified electrical specs, validated SOT23-5L pin mapping, real-world load/line transient behavior, and direct alternatives for battery-powered VCO, ADC, and image sensor power rails.

Technical Context

The LDLN025M28R uses a bandgap-referenced PMOS pass transistor architecture enabling controlled quiescent current (12 μA no-load, ≤425 μA at 250 mA) even in dropout, with internal soft-start and logic-controlled shutdown (<1 μA off-state). Its bias generator and thermal protection circuitry ensure stable operation under varying junction temperatures up to 125 °C.

Designed for ceramic-capacitor stability, it requires only 1 μF input and output capacitance (ESR 5–500 mΩ), supports output discharge via 230 Ω internal resistor, and maintains <5% startup overshoot-critical for powering precision analog front-ends without external sequencing.

Key Specifications

Pinout & Package

SOT23-5L package: 2.95 mm × 1.60 mm × 1.45 mm body, 0.95 mm pitch, exposed pad connected to GND for thermal dissipation (R_thJA = 200 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B282MR-G and ADP160ACBZ-2.8-R7, LDLN025M28R uniquely balances 250 mA drive, 6.5 μVRMS noise, and 250 mV dropout in a thermally optimized SOT23-5L - making it the only choice for simultaneous high-current, ultra-low-noise, and wide-input-range operation in portable RF/imaging systems.

Availability

LDLN025M28R is available at Aetrix Electronics and suitable for smartphone camera modules, RF transceiver power rails, portable medical sensors, and industrial IoT edge nodes requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for LDLN025M28R 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 noise-sensitive analog and RF circuits in battery-operated portable electronics.

FAQ

What is the minimum input voltage required for LDLN025M28R to maintain regulation at 250 mA?

The minimum input voltage is 3.05 V, calculated as V_OUT + V_DROP = 2.8 V + 0.25 V. This holds across -40 °C to +125 °C per datasheet Table 4 (DFN/SOT23 packages). Below this, the device enters dropout and output voltage declines linearly with input.

Can LDLN025M28R be used with tantalum output capacitors?

No - the device is optimized for ceramic capacitors (0.7–10 μF, ESR 5–500 mΩ) as specified in Table 5. Tantalum capacitors typically exhibit higher ESR and aging effects that may compromise stability and transient response, risking oscillation or excessive overshoot during load steps.

Is the NC pin (Pin 4) in SOT23-5L electrically isolated or should it be grounded?

Pin 4 is not internally connected and has no electrical function. Per Table 1 and Figure 2, it may be left floating or tied to GND for mechanical reinforcement and improved solder joint reliability - but grounding does not affect electrical performance or thermal behavior.

How does the output discharge feature behave during fast enable toggling?

When EN transitions low, the 230 Ω internal discharge path actively pulls VOUT to GND within ~1 ms (τ ≈ C_OUT × 230 Ω). For a 1 μF output cap, discharge time to 10% VOUT is ~0.5 ms - fast enough to prevent cross-conduction in multi-rail systems but slow enough to avoid EMI spikes during normal enable cycling.