STMicroelectronics LD39015M12R

Overview

LD39015M12R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator delivering a fixed 1.2 V output with ±2.0% accuracy at 25 °C, 80 mV typical dropout at 100 mA, and 29 µVRMS output noise (1.1–100 kHz) without bypass capacitor. It operates from 1.5 V to 5.5 V input, features logic-controlled shutdown (<1 µA OFF current), and is stable with 1 µF ceramic output capacitors.

For engineers reviewing the LD39015M12R datasheet, LD39015M12R pinout, LD39015M12R application, or LD39015M12R equivalent, key selection criteria include dropout performance under light/heavy load, noise-sensitive analog rail requirements, thermal behavior in SOT23-5L, and enable-controlled power sequencing in compact battery-powered systems.

Technical Context

The LD39015M12R employs a bandgap reference trimmed to 1.22 V and internal resistive feedback (R1/R2) to regulate 1.2 V output. Its PMOS pass transistor enables ultra-low dropout and eliminates reverse current flow.

Enable control is CMOS-compatible with logic-high threshold ≥0.9 V and logic-low ≤0.4 V; shutdown disables bias circuitry to achieve sub-µA quiescent current. Thermal shutdown activates at 160 °C with 20 °C hysteresis, and short-circuit protection limits output current to ~350 mA.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount, 1.45 mm × 1.60 mm footprint, 0.95 mm pitch, 0.6 mm max height, ECOPACK® compliant.

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 LD39015M12R uniquely balances ultra-low noise (29 µVRMS), ultra-low I_Q (18 µA), and wide temperature support (−40 °C to +125 °C) in a single SOT23-5L package-making it optimal for high-reliability, battery-constrained industrial and automotive edge nodes.

Availability

LD39015M12R is available at Aetrix Electronics and suitable for wearable health monitors, BLE peripherals, industrial wireless sensors, and automotive cabin modules requiring stable component supply with guaranteed long-term manufacturability.

Supply support for LD39015M12R 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 LD39015 series targets ultra-low-power, noise-sensitive portable electronics-specifically engineered to replace legacy LDOs in space-constrained, battery-operated devices demanding extended runtime and clean analog rails.

FAQ

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

The LD39015M12R requires VIN ≥ VOUT + VDROP = 1.2 V + 0.1 V = 1.3 V minimum under worst-case conditions. However, per datasheet Table 5, dropout is specified at 80 mV typical and 100 mV max at 100 mA; at 150 mA, max dropout rises to 120 mV. Thus, 1.32 V is the practical minimum for guaranteed 150 mA output, though operation down to 1.5 V input is fully characterized and recommended.

Can the LD39015M12R be used with a 0.47 µF output capacitor?

No. The datasheet specifies a minimum 1 µF ceramic output capacitor (X5R/X7R) for stability across all loads and temperatures. Figure 7 (stability region) shows instability risk below 1 µF, especially with ESR < 0.3 Ω. Using 0.47 µF may cause oscillation or poor transient response, violating design validation requirements for production systems.

Does the EN pin require a pull-up resistor when interfaced to an open-drain microcontroller GPIO?

Yes. The EN pin has no internal pull-up; its leakage current is ≤100 nA, so an external pull-up (typically 100 kΩ to VIN) is required to ensure reliable high-state activation when the GPIO is high-impedance or tri-stated. Without it, EN may float near threshold, causing erratic enable/disable behavior or increased quiescent current.

How does thermal performance change when mounted on a 2-layer versus 4-layer PCB?

Thermal resistance junction-to-ambient (R_thJA) is 255 °C/W for the SOT23-5L package on a standard 2-layer board with minimal copper. With a 4-layer board featuring internal ground/power planes and thermal vias under the exposed pad (though SOT23-5L lacks an exposed pad), R_thJA can improve to ~180 °C/W. This allows ~25% higher continuous current before thermal shutdown at 70 °C ambient.