STMicroelectronics L4941BV

Overview

L4941BV from STMicroelectronics is a 5V fixed-output, very low-dropout linear voltage regulator in TO-220 package, delivering up to 1A output current with 450mV typical dropout at full load, 4–8mA quiescent current at 5mA load, and integrated thermal shutdown, short-circuit, and reverse-polarity protection. It is designed for battery-powered industrial and consumer equipment where efficiency and reliability under low VIN–VOUT margin are critical.

For engineers reviewing the L4941BV datasheet, L4941BV pinout, L4941BV application, or L4941BV equivalent, key selection criteria include dropout voltage at 1A, quiescent current vs. load, thermal resistance (RthJC = 3°C/W), reverse polarity tolerance (–15V), and safe-area protection behavior under transient overload.

Technical Context

The L4941BV employs an internal antisaturation circuit to minimize saturation voltage across the pass transistor, enabling stable regulation down to 450mV input–output differential. Its current-limiting architecture combines foldback and peak-sensing elements to sustain 1.6–2.2A short-circuit current while limiting junction temperature rise via thermal shutdown activation at ~150°C.

Reverse polarity protection operates via internal diode clamping between input and ground, allowing –15V reverse input without damage when RO = 100Ω. Output impedance remains ≤30mΩ at 1kHz, supporting fast load transient response in point-of-load configurations.

Key Specifications

Pinout & Package

Package: TO-220 (3-pin, vertical mounting, metal tab connected to GND). Thermal pad is electrically tied to Pin 2 (Ground).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 5V LDO regulator applications.

Compared with LM2940CT-5.0 and TLV1117-50, the L4941BV uniquely combines TO-220 thermal performance (RthJC = 3°C/W), reverse polarity hardening, and sub-500mV dropout at full 1A - making it optimal for ruggedized, high-current, battery-sensitive designs.

Availability

L4941BV is available at Aetrix Electronics and suitable for portable medical monitors, industrial PLC I/O modules, USB-powered test instruments, and smart home sensor hubs requiring stable component supply with long lifecycle visibility.

Supply support for L4941BV 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 analog, microcontroller, power, and sensor solutions for industrial, automotive, and consumer markets.

The L4941BV belongs to ST's legacy linear regulator product line, engineered specifically for robust, low-dropout DC-DC conversion in battery-powered and harsh-environment applications where protection integrity and thermal resilience are non-negotiable.

FAQ

What is the maximum input voltage for continuous operation?

The L4941BV supports continuous forward input voltage up to 16V at 5mA load, per electrical characteristics table. Absolute maximum rating is 30V, but operation above 16V is not guaranteed for regulation stability or thermal safety under full load.

Does the TO-220 package require a heatsink for 1A operation?

Yes - with RthJC = 3°C/W and RthJA = 50°C/W, dissipating 1.5W (e.g., VIN = 8V, VOUT = 5V, IOUT = 1A) raises junction temperature by ~75°C above ambient. A heatsink reducing RthJA to ≤25°C/W is recommended for reliable 1A operation at 70°C ambient.

Can the L4941BV be used with ceramic output capacitors?

Yes - the datasheet specifies stability with CO = 22µF ceramic capacitor (and CI = 0.1µF), eliminating ESR requirements. This simplifies layout and improves reliability versus electrolytic alternatives prone to drying out.

Is reverse polarity protection active during startup or only steady-state?

Reverse polarity protection is inherent to the internal structure and active at all times - including power-up, shutdown, and transient conditions. The –15V absolute maximum rating applies regardless of output load or input slew rate, verified per JEDEC JESD78 testing.