STMicroelectronics L5956

Overview

L5956 from STMicroelectronics is a multifunction automotive voltage regulator IC integrating four independent LDO regulators (8.5 V/500 mA, 5 V/300 mA permanent, 5 V/800 mA, 3.3 V/800 mA) and a 2 A high-side power switch, with ignition monitoring, reset generation, load dump protection, and thermal shutdown - deployed in car radio head units for stable multi-rail power delivery under harsh battery conditions.

For engineers reviewing the L5956 datasheet, L5956 pinout, L5956 application, or L5956 equivalent, this page delivers verified regulator output specs, validated thermal performance (R_{th j-case} = 1.5 °C/W in PowerSO20), real-world protection thresholds (V_{HOLD_L} = 9–10 V, V_IGNIN rising = 1.18–1.27 V), and confirmed package-specific ESD protection on all pins.

Technical Context

The L5956 implements four independent linear regulators with separate input paths (Vin1 for REG1 and standby 5 V; Vin2 for dual 5 V and 3.3 V outputs), each featuring internal current limiting (0.6–2 A), dropout voltages from 0.6 V to 2.5 V, and ≥50 dB PSRR at 1 kHz. The integrated high-side switch provides controlled load activation with peak current capability (2–3.5 A for <15 ms) and delay-protected short-circuit response (SWDEL = 15–40 ms).

Its monitoring subsystem includes a Schmidt-trigger ignition buffer (V_TH(R) = 1.18–1.27 V, V_TH(F) = 1.03–1.17 V), a push-pull reset buffer with programmable delay (C_RES = 47 nF → 10–60 ms), and dual-threshold hold logic (low-detect: 9–10 V; high-detect: 18–22 V) enabling robust battery condition tracking in automotive start-stop cycles.

Key Specifications

Pinout & Package

Available in two automotive-grade packages: PowerSO20 (slug-up, R_{th j-case} = 1.5 °C/W) and Multiwatt 15 (vertical, R_{th j-case} = 1.8 °C/W). Both feature exposed thermal pads for direct heatsink mounting and comply with ECOPACK® environmental standards.

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 L5956 uniquely combines four precision LDOs, a protected high-side switch, and automotive-grade monitoring in one die - eliminating six discrete components and enabling single-layer PCB routing for cost-sensitive car audio platforms.

Availability

L5956 is available at Aetrix Electronics and suitable for car radio head units, infotainment control modules, and telematics gateways requiring stable component supply across extended temperature (-40°C to +85°C) and high-reliability automotive qualification.

Supply support for L5956 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 L5956 belongs to ST's Automotive Power Management IC family, engineered specifically for cost-optimized, high-integration power delivery in 12 V vehicle infotainment systems - emphasizing low quiescent current, transient resilience, and functional safety-aware monitoring.

FAQ

What is the maximum allowable input voltage for L5956 during load dump events?

The L5956 withstands transient supply voltages up to 50 V on both VIN1 and VIN2 pins per absolute maximum ratings (Table 2), enabling direct connection to automotive battery rails without external TVS clamping. This rating applies for short-duration transients defined in ISO 7637-2 Pulse 5a, and sustained operation above 30 V DC is prohibited.

How does the ignition comparator function differ from standard voltage monitors?

The L5956's IGNIN input uses a Schmidt-trigger buffer with hysteresis (50 mV typical) and precise thresholds (rising: 1.18–1.27 V; falling: 1.03–1.17 V), allowing reliable detection of 12 V system presence despite battery ripple and alternator noise. Unlike generic comparators, it drives an internal logic block that directly controls HOLD and RESET timing without external components.

Can the 3.3 V regulator (REG4) be used as the primary supply for an ARM Cortex-M microcontroller?

Yes - REG4 delivers 3.3 V ±150 mV at up to 800 mA with ≤100 mV load regulation and ≥50 dB PSRR at 1 kHz, meeting typical requirements for Cortex-M0/M3/M4 cores. Its 2.5 V dropout at full load mandates VIN2 ≥5.8 V; for optimal margin, maintain VIN2 ≥7 V during cranking (9 V minimum).

Is thermal derating required when using the PowerSO20 package at 85°C ambient?

Yes - with R_{th j-case} = 1.5 °C/W and max junction temperature of 150°C, the allowable power dissipation at T_case = 85°C is 43 W (per Table 2), but practical derating begins at T_amb > 70°C due to PCB copper area limitations. For continuous 2 A switch operation, forced airflow or heatsink contact is recommended above 65°C ambient.