STMicroelectronics LD39030SJ12R

Overview

LD39030SJ12R from STMicroelectronics is a 300 mA low-noise, low-quiescent-current LDO voltage regulator delivering a fixed 1.2 V output with ±2.0 % accuracy at 25 °C. It operates from 1.5 V to 5.5 V input, features 200 mV typical dropout at full load, 30 μV_RMS output noise (1–100 kHz), and logic-controlled shutdown consuming ≤1 μA in off mode. It powers core rails in battery-powered portable electronics requiring stable, clean, low-power supply.

For engineers reviewing the LD39030SJ12R datasheet, LD39030SJ12R pinout, LD39030SJ12R application, or LD39030SJ12R equivalent, key selection criteria include dropout voltage at 300 mA, quiescent current across temperature, soft-start timing, ceramic capacitor compatibility (1 μF min), and thermal shutdown behavior at 160 °C.

Technical Context

The LD39030SJ12R integrates a bandgap reference, trimming network, and internal soft-start circuit that ramps output over ~100 μs to limit inrush current. Its flip-chip 4-bump construction enables compact layout and low thermal resistance (R_thJA = 180 °C/W).

It uses a PMOS pass transistor architecture enabling ultra-low dropout and near-zero reverse current during shutdown. Enable logic (EN) controls operation with 0.4 V max low threshold and 0.9 V min high threshold across –40 °C to 125 °C, while internal current limiting and thermal protection ensure robustness under fault conditions.

Key Specifications

Pinout & Package

LD39030SJ12R uses a flip-chip 4-bump package (0.8 × 0.8 mm, 0.4 mm pitch) with exposed die pad for thermal conduction. The package is ECOPACK®-compliant and designed for reflow soldering on standard PCB footprints.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B122MR-G and RT9013-12GB, LD39030SJ12R delivers superior noise performance, integrated soft-start, and lower quiescent current-making it optimal for space-constrained, battery-sensitive designs where signal integrity and startup reliability are critical.

Availability

LD39030SJ12R is available at Aetrix Electronics and suitable for mobile phones, digital still cameras, cordless telephony, and PDA systems requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for LD39030SJ12R 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.

LD39030SJ12R belongs to ST's LD39xx ultra-low-noise LDO family, engineered specifically for portable battery-powered devices demanding minimal power loss, high PSRR, and robust thermal behavior in sub-1 mm² packages.

FAQ

What is the minimum input voltage required for LD39030SJ12R to regulate 1.2 V output at 300 mA?

The minimum input voltage is determined by dropout: 1.2 V + 0.2 V = 1.4 V. However, the absolute minimum operating input is specified as 1.5 V in datasheet Table 5, and the UVLO turn-on threshold is 1.45 V. Therefore, reliable regulation at full load requires VIN ≥ 1.5 V, with margin for line drop and tolerance.

Can LD39030SJ12R be used with a 0.47 μF ceramic output capacitor?

No. The datasheet specifies a minimum C_OUT of 1 μF for stability (Section 7, Figure 21). Using 0.47 μF risks oscillation due to insufficient phase margin, especially with low-ESR ceramics. Stability is guaranteed only within the 1–22 μF range with ESR <2 Ω @100 kHz.

Does LD39030SJ12R support adjustable output voltage via external resistors?

No. LD39030SJ12R is a fixed-output variant (1.2 V) with internal feedback divider. Adjustable versions (e.g., LD39030SJ-ADJ) exist but require different order codes and external resistor networks; this part has no FB or ADJ pin and cannot be reconfigured.

How does the enable pin behave during power sequencing with a microcontroller GPIO?

The EN pin accepts standard CMOS logic levels: <0.4 V (max) for shutdown, >0.9 V (min) for activation across –40 °C to 125 °C. A 3.3 V or 1.8 V GPIO can drive it directly; no level-shifting is needed. Input current is ≤100 nA, so GPIO drive strength is not a concern.