STMicroelectronics L5954

Overview

L5954 from STMicroelectronics is a multifunction automotive power management IC integrating five low-dropout voltage regulators (10 V/350 mA, 8.5 V/175 mA, 5 V/350 mA, 5 V/250 mA, and programmable 8 V/10 V @ 1 A) and three high-side drivers (2 A, 0.45 A, 0.45 A), designed specifically for car radio audio systems. It supports I²C-controlled output enable/disable, individual thermal shutdown, load dump protection up to 34 V, and operates across -40 °C to +85 °C.

For engineers reviewing the L5954 datasheet, L5954 pinout, L5954 application, or L5954 equivalent, this device is selected for multi-rail automotive infotainment power delivery where regulated 5 V, 8.5 V, 10 V supplies and controlled high-side switching are required - with attention to standby current (<2 µA), dropout voltage (≤950 mV), and I²C address (0x10).

Technical Context

The L5954 implements independent current limiting per regulator and driver, with thermal shutdown thresholds differentiated by function: 160 °C for REG1–REG5 and HSD2/HSD3, and 170 °C for HSD1. Each regulator uses internal bandgap or VREF-referenced architecture - notably REG3 is referenced to the external VREF pin to minimize offset between parallel 5 V rails.

I²C interface operates at 100–400 kHz, with bit b5 in the data byte selecting REG4's output voltage (8 V if b5 = 0, 10 V if b5 = 1). Standby mode reduces total quiescent current to ≤2 µA when all outputs are disabled, while reverse battery protection must be implemented externally.

Key Specifications

Pinout & Package

Package: Multiwatt15 (vertical, 15-pin, through-hole), thermal resistance R_{th j-case} = 2 °C/W.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLE4271-2 and UC2843BD1R2G, the L5954 uniquely integrates five LDOs, three high-side drivers, and I²C configurability in one Multiwatt15 package - delivering system-level power consolidation unattainable with either alternative.

Availability

L5954 is available at Aetrix Electronics and suitable for car radio power systems, infotainment head units, and automotive audio amplifier biasing requiring stable component supply, long-lifecycle support, and automotive-grade qualification.

Supply support for L5954 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, MCU, power, and automotive ICs since 1987.

The L5954 belongs to ST's automotive power management product line, engineered specifically for cost-sensitive, space-constrained car audio systems requiring consolidated multi-rail regulation and intelligent load switching.

FAQ

What is the I²C address of the L5954 and how is it configured?

The L5954 has a fixed 7-bit I²C address of 0x10 (0001000b), with no hardware address pins. It supports standard-mode (100 kHz) and fast-mode (400 kHz) operation. The address is used for write-only control of REG1, REG4, REG5, and all three high-side drivers; no read-back capability is provided for output states.

Does the L5954 include reverse battery protection?

No, the L5954 does not integrate reverse battery protection. The datasheet explicitly states that external components must be implemented to protect against reverse polarity connection. This is a mandatory design requirement for automotive deployment, as the IC will be damaged if BAT is connected to GND and GND to BAT.

How is the 8 V / 10 V output of REG4 selected?

REG4's output voltage is selected by bit b5 in the I²C data byte: when b5 = 0, REG4 delivers 8 V; when b5 = 1, it delivers 10 V. This selection is performed during I²C write operations to the control register and takes effect immediately upon successful ACK. No additional configuration or timing delay is required.

What is the purpose of the VREF pin (Pin 3) and which regulator uses it?

The VREF pin (Pin 3) provides an external reference input exclusively for REG3 (5 V / 350 mA). Using an external reference instead of the internal bandgap minimizes voltage offset between REG3 and other 5 V supplies (e.g., REG5), achieving ≤40 mV mismatch - critical for matched analog audio supply rails in car radios.