STMicroelectronics L4936N

Overview

L4936N from STMicroelectronics is a dual monolithic voltage regulator IC designed for automotive microcomputer power supply systems, featuring a precision 5V ±2% standby output (VO1), a tracked and programmable main output (VO2) adjustable from 5V to 20V, 50mA/500mA output current capability, <250µA quiescent current in standby mode, and integrated power-on reset with external capacitor–defined delay.

For engineers reviewing the L4936N datasheet, L4936N pinout, L4936N application, or L4936N equivalent, this device supports critical low-dropout dual-rail regulation, early undervoltage warning, thermal/short-circuit protection, and enable-controlled output shutdown-key considerations for engine control units, body control modules, and automotive infotainment power architectures.

Technical Context

The L4936N integrates two independent low-dropout linear regulators: VO1 uses an isolated-collector vertical PNP structure enabling dropout as low as 0.1V at 10mA and operation down to 2V input, while VO2 tracks VO1 or is set via external resistor divider on the ADJ pin, supporting programmable output up to 20V with 500mA capability. Both outputs are protected by foldback current limiting.

Its auxiliary functions include a dedicated reset circuit sensing VO1 with 4.7V threshold and user-defined delay (via CT capacitor), a sense comparator (1.23V reference) for early undervoltage detection on SI pin, and EN-controlled VO2 disable with 30–200mV hysteresis-enabling robust system-level power sequencing and fault monitoring in 12V/24V automotive environments.

Key Specifications

Pinout & Package

Package: Multiwatt-11 (vertical mounting, tab connected to Pin 6/GND), thermally rated R_thj-case = 3°C/W, compatible with standard TO-220 heatsinks.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output automotive voltage regulation applications.

Compared with TLF4936B, the L4936N offers identical pinout and basic functionality at lower cost but lacks safety diagnostics and extended temp rating; versus MC33269DT-5.0, it delivers full dual-rail + supervision in one package, reducing design complexity despite higher IQ.

Availability

L4936N is available at Aetrix Electronics and suitable for engine control units, body control modules, infotainment head units, and ADAS camera ECUs requiring stable component supply across long automotive production lifecycles.

Supply support for L4936N 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 broad manufacturing and qualification expertise.

The L4936N belongs to ST's automotive analog power regulator product line, engineered specifically to consolidate multiple power-supply functions-dual LDO regulation, reset generation, and undervoltage monitoring-into a single AEC-Q100–capable package for microcontroller-based vehicle subsystems.

FAQ

What is the maximum allowable input voltage for continuous operation?

The L4936N supports continuous DC supply voltage up to 25V on the VS1/VS2 pin, with absolute maximum rating of 28V. Transient operation up to 40V is permitted for durations under 1 second, complying with ISO 7637-2 Pulse 5a load-dump specifications common in 12V automotive systems.

How is the reset delay time calculated and adjusted?

The reset delay time t_RD is determined by the external capacitor CT connected to the CT pin: t_RD = CT × 2V / 2µA. For example, a 100nF capacitor yields a nominal delay of 100µs. The actual delay varies from 55µs to 180µs depending on CT tolerance and process variation, as specified in the electrical characteristics table.

Can the L4936N be used outside automotive applications?

Yes-the L4936N is suitable for any industrial or embedded system requiring dual regulated outputs with low quiescent current, programmable voltage, and integrated supervision. Its 40V transient rating and –40°C to +150°C operating range make it viable for off-road equipment, marine electronics, and telecom power subsystems where reliability under voltage stress is critical.

What thermal derating applies when using the Multiwatt-11 package without a heatsink?

With R_thj-case = 3°C/W and typical R_{thcase-ambient} ≈ 60°C/W for still air, total thermal resistance exceeds 63°C/W. At 500mA VO2 load with 12V input, power dissipation reaches ~3.5W, causing >220°C junction rise-exceeding 150°C limit. A minimum heatsink (R_th ≤ 11°C/W) is mandatory for full-load operation per datasheet PD rating at TA = 80°C.