STMicroelectronics LD39015XG12R

Overview

LD39015XG12R from STMicroelectronics is a 150 mA ultra-low-dropout linear regulator with fixed 1.2 V output, 80 mV typical dropout at 100 mA, 18 µA typical quiescent current at no load, and 29 µVRMS output noise at 0.8 V (measurable at 1.2 V per design scaling), designed for power management in space-constrained, battery-powered portable electronics.

For engineers reviewing the LD39015XG12R datasheet, LD39015XG12R pinout, LD39015XG12R application, or LD39015XG12R equivalent, key selection criteria include dropout voltage under 100 mA load, shutdown current <1 µA, ±2.0% output accuracy at 25 °C, ceramic capacitor compatibility (1 µF COUT), and thermal protection up to 160 °C junction temperature.

Technical Context

The LD39015XG12R implements a bandgap-referenced feedback loop with internal trimming for 1.2 V output accuracy, enabling stable regulation across -40 °C to +125 °C. Its enable-controlled shutdown path reduces total supply current to ≤1 µA, while internal thermal foldback and short-circuit current limiting (350 mA) ensure robustness during fault conditions.

Supply voltage rejection is 65 dB at 1 kHz and maintains ≥62 dB at 10 kHz, supporting clean power delivery in noisy mixed-signal environments. The device achieves stability with 1 µF ceramic output capacitance without requiring an external bypass capacitor - a direct result of its low-noise architecture and optimized internal compensation.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount plastic package with exposed pad (no thermal pad connection required), footprint compliant with JEDEC MO-178AA, 2.95 mm × 1.60 mm body size, 0.95 mm pitch.

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, the LD39015XG12R delivers superior noise performance (29 µVRMS) and lowest dropout (80 mV), making it optimal for battery-critical, noise-sensitive applications - though its 150 mA rating matches XC6210 but falls short of RT9013's 200 mA capability.

Availability

LD39015XG12R is available at Aetrix Electronics and suitable for mobile phone baseband power, wearable sensor node regulation, and Bluetooth LE audio earbud supply requiring stable component supply across extended production lifecycles.

Supply support for LD39015XG12R 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, specializing in automotive, industrial, and power management ICs with strong analog and mixed-signal design heritage.

The LD39015 series belongs to ST's high-efficiency, ultra-low-noise LDO portfolio, engineered specifically for battery-powered portable equipment demanding minimal quiescent current, wide input range, and guaranteed stability with ceramic capacitors.

FAQ

What is the minimum input voltage required for stable 1.2 V output at 150 mA?

The LD39015XG12R requires VIN ≥ VOUT + VDROP = 1.2 V + 0.1 V = 1.3 V to sustain 150 mA output, based on maximum dropout of 100 mV over temperature. At room temperature and 100 mA load, typical dropout is 80 mV, so 1.28 V input suffices - but 1.3 V is the conservative design margin per datasheet Section 5.

Can the LD39015XG12R operate with a 0.47 µF output capacitor?

No - the device requires ≥1 µF ceramic output capacitance for guaranteed stability, as confirmed in Table 5 (COUT = 1 µF min.) and Figure 7 (stability region). Using 0.47 µF risks oscillation or excessive load-transient overshoot, especially above 50 mA load steps.

Is the NC pin (Pin 4) safe to connect to ground?

Yes - Pin 4 is internally unconnected and may be left floating or tied to GND without affecting operation or reliability. ST's datasheet explicitly states "Not connected" in Table 2 and confirms no internal bond wire; grounding it improves mechanical solder joint integrity and EMI shielding without electrical consequence.

Does the 29 µVRMS noise specification apply directly to the 1.2 V version?

Yes - although measured at 0.8 V in the datasheet (Section 5, eN parameter), the noise spectral density scales linearly with output voltage; thus 29 µVRMS × (1.2/0.8) = ~43.5 µVRMS would be expected. However, ST specifies 29 µVRMS as the guaranteed maximum across all output voltages including 1.2 V, per footnote in Table 5 and typical performance curves.