STMicroelectronics LD39015M33R

Overview

LD39015M33R from STMicroelectronics is a 150 mA ultra-low-noise, low-quiescent-current LDO voltage regulator delivering fixed 3.3 V output with ±2.0% accuracy at 25 °C, 80 mV typical dropout at 100 mA, and 29 µV_RMS output noise (1.1–100 kHz) without bypass capacitor - designed for power-sensitive battery-operated systems such as mobile phones and PDAs.

For engineers reviewing the LD39015M33R datasheet, LD39015M33R pinout, LD39015M33R application, or LD39015M33R equivalent, key selection criteria include guaranteed 150 mA load capability, logic-controlled shutdown (<1 µA OFF current), SOT23-5L package compatibility with 1 µF ceramic output capacitors, and operation across –40 °C to 125 °C junction temperature.

Technical Context

The LD39015M33R employs a bandgap reference trimmed to 1.22 V with internal resistive feedback (R1/R2) to set 3.3 V output. Its enable-controlled NMOS pass transistor architecture enables fast 30 µs turn-on and supports ultra-low dropout via optimized gate drive under light-to-full load.

Stability is ensured with ≥1 µF ceramic output capacitance and ESR <2.4 Ω; PSRR reaches 65 dB at 1 kHz but rolls off above 10 kHz, while thermal shutdown activates at 160 °C with 20 °C hysteresis and internal current limiting caps short-circuit current at 350 mA.

Key Specifications

Pinout & Package

SOT23-5L package: 5-pin surface-mount, 2.95 mm × 1.60 mm footprint, 0.95 mm pitch, 0.6 mm max height, RoHS-compliant ECOPACK®2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XC6210B332MR-G and AP7361-C33YG-7, the LD39015M33R uniquely balances ultra-low noise, sub-1 µA shutdown, and integrated enable in a space-constrained SOT23-5L - making it optimal for battery-limited, noise-sensitive, and GPIO-controlled applications where full 300 mA is unnecessary.

Availability

LD39015M33R is available at Aetrix Electronics and suitable for mobile phone power rails, wearable sensor subsystems, and industrial IoT edge nodes requiring stable component supply with guaranteed long-term availability and consistent parametric performance.

Supply support for LD39015M33R 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 with emphasis on energy efficiency and reliability.

The LD39015 series belongs to ST's high-performance analog LDO portfolio, engineered specifically for ultra-low-power, low-noise portable and embedded applications where battery life, signal integrity, and thermal robustness are critical design constraints.

FAQ

What is the minimum input voltage required for the LD39015M33R to regulate 3.3 V?

The LD39015M33R requires a minimum input voltage of 3.38 V to maintain regulation at full 150 mA load, based on its 80 mV typical dropout voltage. At lighter loads, regulation is sustained down to 1.5 V input, but output drops below 3.3 V when VIN falls below (VOUT + VDROP); UVLO disables operation entirely below 1.45 V.

Can the LD39015M33R be used with a 1 µF ceramic output capacitor?

Yes - the LD39015M33R is explicitly characterized and stable with a 1 µF X5R/X7R ceramic capacitor (ESR ≤2.4 Ω at 100 kHz). This eliminates need for larger or higher-ESR capacitors and simplifies layout in space-constrained designs.

Does the LD39015M33R require an input capacitor?

Yes - ST recommends ≥1 µF ceramic input capacitor placed close to the IN and GND pins to suppress high-frequency noise and improve transient response. The datasheet confirms stability and performance validation assumes CIN = 1 µF.

How does the enable pin behave during power-up?

The EN pin is active-high with V_IH ≥ 0.9 V (min) and V_IL ≤ 0.4 V (max). When EN rises above 0.9 V, output reaches 95% of 3.3 V within 30 µs. If EN is left floating, internal pull-down ensures default shutdown - external pull-up is required for automatic startup.