STMicroelectronics L4952D

Overview

L4952D from STMicroelectronics is a monolithic automotive voltage regulator in SO20 (12+4+4) package, designed specifically for car radio power management. It delivers a fixed 8.6 V ±0.2 V output at up to 150 mA, features dual low-drop AM/FM switching outputs (OUT2/OUT3), integrated diagnostic output (DIAG), and driver circuitry for an external PNP high-side switch - all optimized for audio subsystems in vehicle infotainment systems.

For engineers reviewing the L4952D datasheet, L4952D pinout, L4952D application, or L4952D equivalent, key selection criteria include its 0.11–0.6 V dropout at 100–150 mA load, 8.6 V ±0.2 V regulation accuracy, thermal shutdown (>150 °C), diagnostic drop detection threshold (0.7–1.3 V), and EN-controlled standby mode with <20 µA quiescent current.

Technical Context

The L4952D integrates four regulated outputs: OUT1 (8.6 V, 150 mA), OUT4 (10.0 V, 3 mA), and two digitally controlled switches (OUT2/OUT3) with EN2/EN3 logic inputs. Its internal bandgap reference and error amplifier ensure stable regulation under automotive supply transients (up to +52 V for 400 ms).

It implements fault protection via thermal shutdown (>150 °C), short-circuit limiting on OUT1, and diagnostic monitoring of output voltage drop - triggering DIAG low when ΔVout exceeds 30–200 mV - enabling loudspeaker mute during rail collapse. The HSSD/HSON interface drives external PNP transistors with built-in drop monitoring and auto-shutdown on overvoltage.

Key Specifications

Pinout & Package

Package: SO20 (12+4+4) - surface-mount, 20-pin small-outline with extended lead frame for thermal dissipation (R_{th j-amb} = 60 °C/W with 2 cm² PCB copper pour).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar automotive radio voltage regulation applications.

Compared with TDA7319 and L4953D, the L4952D offers unique AM/FM switching control and external PNP driver functionality - making it irreplaceable in discrete tuner power architectures where signal-path integration is not required.

Availability

L4952D is available at Aetrix Electronics and suitable for automotive infotainment systems, car radio tuner modules, and vehicle telematics platforms requiring stable component supply under harsh electrical environments.

Supply support for L4952D 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, specializing in automotive, industrial, and power management ICs with broad manufacturing and qualification capabilities.

The L4952D belongs to ST's automotive power management product line, engineered specifically for car radio subsystems requiring multi-rail regulation, fault diagnostics, and AM/FM band switching - not general-purpose voltage regulation.

FAQ

What is the purpose of the DIAG output?

The DIAG output is an open-drain fault indicator that goes low when OUT1 voltage drops more than 30–200 mV below nominal (e.g., due to overload or supply sag) or during thermal shutdown. It connects directly to microcontroller GPIO or audio amplifier mute input to suppress speaker noise before audible artifacts occur.

Can OUT2 and OUT3 be used simultaneously?

Yes - OUT2 and OUT3 are independently controlled by EN2 (high-active) and EN3 (low-active). They share the same 8.6 V input but operate as separate low-drop switches. Simultaneous activation is electrically permitted and commonly used for powering hybrid AM/FM receivers with shared analog front-ends.

What thermal design is required for full 150 mA operation?

To sustain 150 mA at maximum ambient temperature, a minimum 2 cm² copper pour connected to GND pins acts as an onboard heatsink, achieving R_{th j-amb} = 60 °C/W. Without this, junction temperature exceeds 150 °C under worst-case load and ambient, triggering thermal shutdown.

How does the HSS driver protect the external PNP transistor?

The HSS driver monitors voltage drop across the external PNP (via HSON feedback) and compares it to an internal 0.7–1.3 V threshold. If drop exceeds this range - indicating saturation or overcurrent - it disables the driver output within microseconds, preventing thermal destruction while preserving the PNP's safe operating area.