STMicroelectronics L5957

Overview

L5957 from STMicroelectronics is a multifunction voltage regulator IC for automotive car radio systems, integrating four regulated outputs (8.5 V/500 mA, 5 V permanent/300 mA, 5 V/800 mA, 3.3 V/800 mA), a 2 A high-side power switch, ignition comparator, reset buffer, load dump protection, and thermal shutdown. It operates across -40 °C to +85 °C with <70 µA standby quiescent current and supports PowerSO20 (slug up) and Multiwatt15 packages.

For engineers reviewing the L5957 datasheet, L5957 pinout, L5957 application, or L5957 equivalent, this device is selected for multi-rail power management in infotainment head units where supply stability under battery transients (up to 50 V), precise reset timing, and integrated ignition sensing are required.

Technical Context

The L5957 integrates three linear regulators (REG1–REG4) and one high-side driver in a single die, with independent enable controls (ENREG1-4, ENREG3, EN_SW) and dedicated monitoring blocks: a push-pull reset buffer with 47 nF capacitor delay, an ignition comparator with Schmitt-trigger hysteresis (30–100 mV), and a hold circuit detecting VIN1 thresholds at 9.5 V (low) and 20 V (high). All regulators feature internal current limiting and dropout voltages specified at full load (e.g., 0.6 V for REG1 at 500 mA).

Protection architecture includes load dump tolerance (22 V on VIN1/VIN2), thermal shutdown activation at ~160 °C junction temperature, short-circuit detection with 15–45 ms SWDEL delay, and ESD protection on all pins per IEC 61000-4-2 Level 4. The IC maintains regulation during cold cranking (VIN1 down to 6 V) and supports backup capacitor retention via the HOLD signal.

Key Specifications

Pinout & Package

Available in PowerSO20 (slug up) and Multiwatt15 (vertical) packages; both expose thermal slug for PCB heatsinking. PowerSO20 offers lower thermal resistance (1.5 °C/W j-case) versus Multiwatt15 (1.8 °C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLE4271-2G and UC2843BD1R2G, the L5957 uniquely combines four precision LDOs, high-side switching, and automotive-grade monitoring in one package-enabling full car radio power architecture without supplemental ICs.

Availability

L5957 is available at Aetrix Electronics and suitable for automotive infotainment systems, car radio head units, and body control modules requiring stable component supply under harsh electrical environments including load dump and cold crank conditions.

Supply support for L5957 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 silicon solutions for automotive, industrial, and consumer markets since 1987.

The L5957 belongs to ST's automotive power management IC product line, engineered specifically for cost-sensitive, space-constrained car audio systems requiring integrated protection, sequencing, and multi-rail regulation.

FAQ

What is the maximum allowable input voltage for L5957 during load dump events?

The L5957 withstands transient supply voltages up to 50 V on VIN1 and VIN2 per absolute maximum ratings. Its internal load dump protection activates at 22 V, clamping energy and maintaining regulation for all outputs without external TVS diodes-meeting ISO 7637-2 Pulse 5a requirements for 12 V automotive systems.

How does the reset function behave during battery voltage sag?

The reset buffer asserts low when REG2 (5 V permanent) drops below 4.7 V (typical falling threshold) and releases when it rises above 4.8 V (typical rising threshold), providing 100–200 mV hysteresis. Reset delay is programmable via external CRES (e.g., 47 nF yields 10–60 ms delay), ensuring reliable µP reset before brownout.

Can L5957 operate with input voltage below 6 V, such as during cold cranking?

Yes-the L5957 supports VIN1 down to 6 V for REG2 and the power switch, and VIN2 down to 6 V for REG3/REG4. For extended operation below 6 V, the BU (boost) pin accepts external boosted voltage to sustain regulation, enabling compatibility with cold crank profiles per ISO 16750-2.

What thermal management is required for continuous 2 A high-side switch operation?

At 2 A DC load, the power switch dissipates up to 1 W (Vdrop ≈ 0.5 V). Using the PowerSO20 package with thermal resistance Rth(j-case) = 1.5 °C/W, a 25 °C ambient with 10 cm² copper pour achieves ~65 °C case temperature-well below the 150 °C max junction limit. No forced airflow is required for typical automotive cabin environments.