STMicroelectronics L4936E

Overview

L4936E from STMicroelectronics is a monolithic dual-output voltage regulator IC designed for microcomputer-controlled automotive systems. It delivers two stabilized outputs: 5V ±1% @ 100mA (OUT1) and 5V ±2% @ 400mA (OUT2), with ultra-low quiescent current (65μA in standby), adjustable reset threshold (3.8–4.7V), and protection against −5V negative transients on EN/SI pins.

For engineers reviewing the L4936E datasheet, L4936E pinout, L4936E application, or L4936E equivalent, key selection considerations include dual-output dropout performance, integrated power-on reset with programmable delay, sense comparator functionality for supply monitoring, and Multiwatt-11 thermal design compatibility in harsh automotive environments.

Technical Context

The L4936E integrates two independent low-dropout regulators: OUT1 uses an isolated-collector vertical PNP transistor enabling operation down to 3V input while maintaining regulation up to 40V transient supply; OUT2 employs the same topology rated for 400mA, with ADJ feedback enabling fixed or adjustable output via external resistor divider.

Its embedded functions include a precision reset generator (programmable threshold via PR pin, 40–140ms delay via CT capacitor), a sense comparator referenced to 1.23V with 10–60mV hysteresis, and ESD-protected EN/SI inputs capable of withstanding −5V transients - all coordinated under a single thermal shutdown scheme where OUT2 disables ~10K before OUT1.

Key Specifications

Pinout & Package

Package: Multiwatt-11 (vertical mounting, tab connected to Pin 6/GND), R_{th j-case} = 3°C/W, rated for 5W dissipation at T_amb = 80°C with 8 cm² copper ground plane.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLF49400ESV50 and MAX16910ATP+, the L4936E uniquely combines dual independent LDOs, −20V–+20V sense flexibility, and resistor-programmable reset threshold - making it optimal for legacy automotive designs requiring full supply supervision and minimal external components.

Availability

L4936E is available at Aetrix Electronics and suitable for engine control units, body control modules, ADAS camera systems, and infotainment head units requiring stable component supply across extended temperature and transient conditions.

Supply support for L4936E 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 L4936E belongs to ST's automotive-grade linear regulator product line, engineered specifically for microcontroller power delivery in harsh-temperature, high-transient automotive environments - emphasizing integration, reliability, and functional safety readiness.

FAQ

What is the maximum allowable input voltage for continuous operation?

The L4936E supports continuous DC supply voltage from 5V to 28V on both VS1 and VS2 pins. Transient operation up to +40V or down to −14V is permitted for durations under 400ms, per absolute maximum ratings. Sustained operation above 28V risks permanent damage even if within transient limits.

How is the reset delay time calculated and what capacitor value achieves 100ms nominal delay?

The nominal reset delay is calculated as t_{RD nom} ≈ C_T × 1.4V / 1μA. For 100ms, solve C_T = (100ms × 1μA) / 1.4V ≈ 71.4nF. A standard 68nF or 75nF capacitor yields 96–105ms delay. Ensure C_T leakage <0.5mA at 2V and place close to the CT pin with short traces.

Can OUT2 be adjusted to voltages other than 5V, and what is the minimum external resistor tolerance required?

Yes - connecting an external resistor divider between ADJ and OUT2 allows adjustment using V_OUT2 = V_OUT1(1 + R_1E(R_2E+R_ADJ)/R_2ER_ADJ). Since R_ADJ is 60–150kΩ with −2000ppm/°C tempco, 1% metal-film resistors are recommended to maintain ±2% output accuracy across −40°C to +150°C.

Is thermal shutdown coordinated between OUT1 and OUT2, and how does it affect system behavior?

Yes - thermal shutdown is coordinated: OUT2 disables at ~155°C (10K below OUT1's 165°C trip), allowing partial functionality to continue while reducing chip power. This staged shutdown prevents sudden system collapse, enabling graceful firmware response (e.g., logging thermal event) before full regulator shutdown occurs.