STMicroelectronics LDLN025J18R

Overview

LDLN025J18R from STMicroelectronics is a 250 mA ultra-low-noise low-dropout (LDO) voltage regulator in Flip-Chip4 package, delivering 1.8 V output with ±2% accuracy across -40 °C to +125 °C, 6.5 μVRMS noise (10 Hz–100 kHz), and 250 mV dropout at full load. It operates from 1.5 V to 5.5 V input and features logic-controlled shutdown (<1 μA off-state current), internal soft-start, and output discharge.

For engineers reviewing the LDLN025J18R datasheet, LDLN025J18R pinout, LDLN025J18R application, or LDLN025J18R equivalent, this LDO is selected for noise-sensitive analog/RF power rails where PSRR (>60 dB @ 100 kHz), quiescent current control (12 μA no-load), thermal robustness, and ceramic-capacitor stability are critical design requirements.

Technical Context

The LDLN025J18R employs a bandgap-referenced error amplifier with PMOS pass transistor architecture, enabling ultra-low dropout and controlled quiescent current even in dropout condition. Its bias generator and thermal protection circuitry ensure stable operation across junction temperatures up to 125 °C.

Designed for single-supply battery-powered systems, it integrates enable logic with internal 1 MΩ pull-down, output discharge path (230 Ω), and overcurrent/thermal shutdown. Stability is guaranteed with 0.7–1 μF ceramic input/output capacitors and ESR ≤500 mΩ.

Key Specifications

Pinout & Package

LDLN025J18R is packaged in Flip-Chip4 (0.41 mm × 0.41 mm, 0.25 mm height), a die-scale chip-scale package with bottom-side I/O bumps requiring solder reflow onto PCB pads. Exposed pad must be connected to GND for thermal and electrical performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B182MR-G and ADP160ACBZ-1.8-R7, LDLN025J18R delivers 39% higher output current, 48% lower integrated noise, and superior thermal performance in a smaller Flip-Chip4 footprint-making it the optimal choice for high-density, noise-critical portable RF and imaging systems.

Availability

LDLN025J18R is available at Aetrix Electronics and suitable for smartphone camera modules, VCO power supplies, portable instrumentation ADCs, and IoT sensor node cores requiring stable component supply with guaranteed long-term availability.

Supply support for LDLN025J18R 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 consumer markets since 1987.

The LDLN025 series belongs to ST's ultra-low-noise LDO product line, engineered specifically for powering noise-sensitive analog and RF circuitry in battery-operated portable electronics where PSRR, dropout, and quiescent current are system-critical parameters.

FAQ

What is the minimum input voltage required for LDLN025J18R to maintain regulation at 250 mA?

The minimum input voltage is calculated as VOUT + VDROP = 1.8 V + 0.25 V = 2.05 V. At 250 mA load and -40 °C to +125 °C, the maximum dropout is 250 mV (per datasheet Table 4). Below 2.05 V, the device enters dropout and output voltage declines linearly with input.

Can LDLN025J18R be used with 0.47 μF output capacitors?

No-0.47 μF is below the minimum recommended 0.7 μF (Table 5). Using 0.47 μF risks instability and excessive load transient overshoot (>40 mV per Table 4), especially with ESR outside the 5–500 mΩ range. Always use ≥0.7 μF X7R ceramic with appropriate ESR.

Does the NC pin on LDLN025J18R require PCB routing or grounding?

The NC pin is not internally connected (Table 1). ST recommends connecting it to GND for mechanical reinforcement and improved thermal conduction via the PCB copper, but it may be left unconnected if board layout constraints prohibit routing. No electrical function is affected either way.

How does the output discharge feature behave during EN pin assertion?

When EN is pulled low, the internal 230 Ω discharge path activates within 150 μs (typical t_ON inverse), actively pulling VOUT to GND. This prevents residual charge from back-powering downstream ICs or causing latch-up in powered-off sections of the system.