STMicroelectronics LD39030SJ25R

Overview

LD39030SJ25R from STMicroelectronics is a 300 mA low-noise, low-quiescent-current LDO voltage regulator with fixed 2.5 V output, 200 mV typical dropout at full load, 20 μA typical quiescent current at no load, and 30 μV_RMS output noise (1 kHz–100 kHz). It operates from 1.5 V to 5.5 V input, features logic-controlled shutdown, internal soft-start (100 μs), and is stabilized with a 1 μF ceramic output capacitor - ideal for powering RF-sensitive analog rails in portable battery-powered systems.

For engineers reviewing the LD39030SJ25R datasheet, LD39030SJ25R pinout, LD39030SJ25R application, or LD39030SJ25R equivalent, key selection criteria include ultra-low noise performance for ADC/DAC reference supplies, sub-1 μA shutdown current for energy harvesting nodes, dropout behavior under dynamic load, and compatibility with miniature flip-chip packaging in space-constrained handheld designs.

Technical Context

The LD39030SJ25R employs a bandgap-referenced error amplifier with internal trimming (1.22 V reference) and thermal/short-circuit protection. Its flip-chip 4-bump construction enables low-inductance, high-frequency stability with minimal PCB footprint.

It integrates an enable-controlled MOSFET pass device with internal soft-start circuitry that limits inrush current by 67% and ensures monotonic V_OUT rise. Supply voltage rejection remains ≥62 dB up to 10 kHz, then rolls off above that frequency due to internal compensation architecture.

Key Specifications

Pinout & Package

LD39030SJ25R uses a flip-chip 4-bump package (0.8 mm × 0.8 mm, 0.4 mm pitch), with exposed die pad for thermal conduction and minimal parasitic inductance. The package is ECOPACK®-compliant and RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B252MR-G and ADP125ARHZ-2.5-R7, the LD39030SJ25R uniquely combines 300 mA capability, 30 μV_RMS noise, 20 μA I_Q, and 0.8 mm × 0.8 mm flip-chip packaging - making it optimal for miniaturized, battery-constrained systems demanding both ultra-low noise and ultra-low power.

Availability

LD39030SJ25R is available at Aetrix Electronics and suitable for mobile phone baseband power, wearable health monitor analog front-ends, digital still camera sensor bias, and Bluetooth LE audio codec power requiring stable component supply across production volumes.

Supply support for LD39030SJ25R 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 LD390xx series targets ultra-low-power, noise-sensitive portable electronics - emphasizing miniature packaging, sub-μA shutdown, and ceramic-capacitor stability for next-generation battery-operated devices.

FAQ

What is the minimum input voltage required to maintain regulation at 2.5 V output?

The LD39030SJ25R maintains regulation down to VIN = VOUT + VDROP = 2.5 V + 0.2 V = 2.7 V under 300 mA load (typical). At lighter loads, dropout decreases - e.g., ~50 mV at 10 mA - enabling operation from as low as 2.55 V input while sustaining 2.5 V output. Below 1.5 V input, the device shuts down per absolute maximum rating.

Can the LD39030SJ25R be used with a 0.47 μF output capacitor?

No. The datasheet specifies 1 μF minimum ceramic output capacitance (X5R/X7R) for stability, validated in Figure 21's ESR/COUT stability zone. Using 0.47 μF risks oscillation or poor transient response, especially under load steps. A 1 μF capacitor is mandatory; 2.2 μF is acceptable and improves PSRR above 10 kHz.

Does the EN pin require an external pull-up resistor?

No. The EN pin has an internal pull-down (I_EN ≤ 100 nA), so it defaults to shutdown when left floating. To activate the regulator, drive EN to ≥0.9 V using a GPIO or dedicated enable signal - no external pull-up is needed or recommended, as it would increase system I_Q.

How does thermal shutdown behave during sustained overload?

When junction temperature reaches 160 °C, the device enters thermal shutdown, disabling the pass transistor and reducing output current to near zero. After cooling by ≥20 °C hysteresis, it automatically resumes regulation without requiring an EN toggle. This cycle repeats if overload persists, protecting against permanent damage during solder reflow or sustained short-circuit conditions.