STMicroelectronics LD39030SJ18R

Overview

LD39030SJ18R from STMicroelectronics is a 300 mA low-noise, low-quiescent-current LDO voltage regulator delivering 1.8 V output with ±2.0 % accuracy at 25 °C, ultra-low dropout (200 mV typ. at 300 mA), and 30 μV_RMS output noise (1 kHz–100 kHz). It features logic-controlled shutdown (<1 μA off-mode current), internal soft-start (100 μs typ.), and ceramic capacitor compatibility (1 μF C_OUT). Designed for space-constrained battery-powered systems like digital still cameras and PDAs.

For engineers reviewing the LD39030SJ18R datasheet, LD39030SJ18R pinout, LD39030SJ18R application, or LD39030SJ18R equivalent, key selection criteria include dropout voltage under 300 mA load, quiescent current behavior across temperature, noise performance at 1.8 V output, and flip-chip 4-bump package footprint compatibility with high-density portable PCB layouts.

Technical Context

The LD39030SJ18R implements a bandgap-referenced feedback loop with internal trimming resistors (R1/R2) and thermal/short-circuit protection. Its enable input controls NMOS pass transistor biasing via dedicated EN logic circuitry, allowing fast transition between active (40 μA typ. I_Q) and shutdown (<1 μA) states.

Soft-start is fully integrated-no external capacitor required-and linearly ramps output voltage over ~100 μs to limit inrush current to one-third of uncontrolled startup. The flip-chip 4-bump construction enables minimal board area usage while maintaining thermal resistance (R_thJA = 180 °C/W) suitable for ambient temperatures up to 125 °C junction.

Key Specifications

Pinout & Package

LD39030SJ18R uses a flip-chip 4-bump package (0.8 mm × 0.8 mm, 0.4 mm pitch) with bottom-side terminations. This ultra-compact construction eliminates wire bonds and reduces parasitic inductance, supporting high-frequency stability with 1 μF ceramic output capacitors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6206P182MR and RT9013-18GB, LD39030SJ18R delivers superior noise performance (30 vs. ≥40 μV_RMS) and smallest footprint (0.64 mm² vs. ≥2.5 mm²), making it optimal for next-generation ultra-compact imaging and communication modules where EMI margin and PCB real estate are critical.

Availability

LD39030SJ18R is available at Aetrix Electronics and suitable for digital still cameras, personal digital assistants (PDAs), cordless phone subsystems, and mobile phone baseband power management requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LD39030SJ18R 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 microcontrollers, power management ICs, sensors, and analog devices for industrial, automotive, and consumer markets.

LD39030SJ18R belongs to ST's LD39030 series of ultra-low-noise, low-I_Q LDOs engineered specifically for battery-powered portable electronics demanding high efficiency, minimal footprint, and clean power delivery under dynamic load conditions.

FAQ

What is the minimum input voltage required for stable 1.8 V output at 300 mA load?

The LD39030SJ18R requires a minimum input voltage of 2.0 V to maintain regulation at 300 mA load, based on its typical 200 mV dropout voltage (V_IN = V_OUT + V_DROP = 1.8 V + 0.2 V). Absolute minimum VIN is 1.5 V, but output cannot be sustained at full current below 2.0 V due to dropout limitations.

Can LD39030SJ18R operate with a 1 μF ceramic output capacitor across the full -40 °C to +125 °C range?

Yes-ST specifies stable operation with 1 μF X5R/X7R ceramic capacitors over the full temperature range. The device's internal compensation and low ESR sensitivity (stable with ESR <2 Ω at 100 kHz) eliminate need for capacitor derating or parallel configurations in most portable applications.

How does the enable pin behave during power sequencing with a 1.2 V host controller?

The EN pin accepts 1.2 V logic directly: V_EN(H) threshold is 0.9 V min, and V_EN(L) is 0.4 V max. When driven by a 1.2 V GPIO, the device activates cleanly without level-shifting; leakage into EN is limited to 100 nA max, preventing unintended wake-up during host sleep states.

Is thermal shutdown recovery automatic after cooling?

Yes-thermal shutdown is fully autonomous and self-resetting. When junction temperature exceeds 160 °C, the device disables output and enters thermal shutdown. Once temperature falls below 140 °C (20 °C hysteresis), regulation resumes automatically without requiring EN pin toggling or external intervention.