STMicroelectronics L5957PD

Overview

L5957PD from STMicroelectronics is a multifunction automotive voltage regulator IC for car radio systems, integrating four regulated outputs (8.5 V/500 mA, 5 V/300 mA permanent, 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 - all in a single PowerSO20 (slug up) package.

For engineers reviewing the L5957PD datasheet, L5957PD pinout, L5957PD application, or L5957PD equivalent, this device serves as a system power manager in infotainment head units requiring multiple rail sequencing, battery monitoring, backup hold functionality, and robust transient protection under ISO 7637-2 conditions.

Technical Context

The L5957PD implements a triple linear regulator architecture with independent enable controls (ENREG1–4, ENREG3, EN_SW) and dedicated monitoring blocks: an ignition input buffer with Schmitt-trigger hysteresis (1.17–1.33 V thresholds), a reset circuit with 47 nF capacitor timing (10–60 ms delay), and a HOLD output that asserts low when VIN1 falls below 9.5 V or rises above 22 V.

Its power switch features current limiting (1–2 A short-circuit peak), 0.5 V typical drop at 1.8 A DC, and 15–45 ms delay before shutdown during overload; regulators use internal compensation compatible with 5–100 µF output capacitors and ESR ≤10 Ω for stability across -40 °C to +85 °C.

Key Specifications

Pinout & Package

Package: PowerSO20 (slug up), thermally enhanced surface-mount package with exposed die attach pad on top side for PCB heatsinking; R_{th j-case} = 1.5 °C/W enables 43 W power dissipation at T_case = 85 °C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLE4271-2G, L5957PD delivers four precision rails and power switching in one package, eliminating six external components; versus UC2843BD1R2G, it trades switching efficiency for deterministic low-noise output, simplified layout, and integrated automotive protection functions.

Availability

L5957PD is available at Aetrix Electronics and suitable for automotive infotainment head units, telematics control units, and instrument cluster displays requiring stable component supply, AEC-Q100-compliant sourcing, and long-term lifecycle support.

Supply support for L5957PD 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 microcontrollers, power management ICs, and automotive-grade analog devices since 1987.

The L5957PD belongs to ST's automotive power management portfolio, engineered specifically for infotainment and body electronics applications demanding multi-rail sequencing, battery monitoring, and ISO 7637-2 transient resilience.

FAQ

What is the maximum allowable input voltage on VIN1 for continuous operation?

VIN1 supports 9–18 V DC for normal operation per datasheet Section 2.3. Absolute maximum rating is 30 V DC, but sustained operation above 18 V violates specification limits and risks regulator instability or thermal shutdown. Transient load dump events up to 22 V (ISO 7637-2 Pulse 5a) are tolerated for ≤400 ms without damage.

Can the 3.3 V and second 5 V regulators be used simultaneously at full load?

Yes - REG3 (5 V/800 mA) and REG4 (3.3 V/800 mA) share VIN2 input and can operate concurrently at rated current. Total power dissipation must stay within 43 W limit; at 14.4 V input and 1.6 A combined output current, junction temperature remains safe with proper heatsinking on the PowerSO20 slug.

How does the HOLD output behave during cold cranking?

HOLD goes low when VIN1 drops below 9.5 V (typical) and remains low until VIN1 exceeds 10 V (hysteresis ~50–200 mV). During cold cranking (typically 6–8 V), HOLD asserts to signal microcontroller that main supply is invalid, enabling graceful shutdown or backup mode activation without relying on software polling.

Is external compensation required for the 8.5 V regulator output?

No - REG1 (8.5 V) uses internal compensation optimized for 5–100 µF ceramic or tantalum output capacitors with ESR between 0.5 Ω and 10 Ω. Figure 4 in the datasheet confirms stability across this range; adding external compensation risks oscillation and violates the validated design.