STMicroelectronics L9951XPTR

Overview

L9951XPTR from STMicroelectronics is an automotive-grade rear door actuator driver IC integrating three half-bridge outputs (OUT1–OUT3) and two high-side drivers (OUT4–OUT5) for controlling DC motors and resistive loads in vehicle door modules. It delivers 7.4 A (OUT1, R_ON = 150 mΩ), 5 A (OUT2/OUT3, R_ON = 200 mΩ), and 1.25 A (OUT4/OUT5, R_ON = 800 mΩ) with SPI-controlled PWM, open-load/overload diagnostics, and <3 µA standby current - deployed in rear door lock, safe-lock, and interior lighting circuits.

For engineers reviewing the L9951XPTR datasheet, L9951XPTR pinout, L9951XPTR application, or L9951XPTR equivalent, key selection considerations include its PowerSSO-36 package, five-channel programmable drive architecture, integrated charge pump for reverse polarity protection, and diagnostic reporting via SPI status register - critical for ASIL-B–aligned body electronics design.

Technical Context

The L9951XPTR implements a microcontroller-driven, SPI-configurable driver architecture with three independent half-bridges (OUT1–OUT3) supporting bidirectional motor control (forward/reverse/brake/high-Z), and two dedicated high-side drivers (OUT4–OUT5) optimized for grounded resistive loads like incandescent bulbs. All outputs feature real-time current monitoring, overtemperature shutdown (T_j = 170 °C), and open-load detection via internal voltage comparators.

Its dual-supply design separates VS (7–28 V, motor power rail) from VCC (4.5–5.3 V, logic supply), enabling robust operation under automotive battery transients. The CM/PWM pin serves as a bidirectional interface: sourcing 1:10,000 current-sense signals (±4% accuracy) or accepting PWM commands to modulate all five outputs simultaneously - with soft-start programmability mitigating inrush currents exceeding rated limits.

Key Specifications

Pinout & Package

Package: PowerSSO-36 - thermally enhanced, exposed-pad surface-mount package with integrated heat slug for automotive under-hood thermal management (R_thJA = 35 °C/W, R_thJC = 2.5 °C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar rear door actuator driver applications.

Compared with VNQ5E160K-E and L9958TR, the L9951XPTR uniquely integrates motor drive, lighting control, diagnostics, and programmable softstart in one PowerSSO-36 package - reducing BOM count and PCB area while enabling centralized door ECU architecture.

Availability

L9951XPTR is available at Aetrix Electronics and suitable for automotive rear door modules, body control units, and OEM door actuator assemblies requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for L9951XPTR 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, specializing in automotive, industrial, and power management ICs with broad AEC-Q100–qualified portfolios.

The L9951XPTR belongs to ST's "Automotive Smart Power" product line, engineered specifically for intelligent, diagnostic-rich actuator control in vehicle body electronics - emphasizing functional safety, thermal resilience, and system-level integration.

FAQ

What is the maximum junction temperature and thermal protection behavior of the L9951XPTR?

The L9951XPTR features two-tier thermal protection: temperature warning triggers at T_j = 150 °C (hysteresis 20 °C), signaling potential overheating via SPI status bit; thermal shutdown activates at T_j = 170 °C (hysteresis 5 °C), disabling all outputs until junction cools to 150 °C. This dual threshold prevents intermittent faults while ensuring fail-safe operation in sealed door cavities.

How does the CM/PWM pin function in current monitoring versus PWM input modes?

The CM/PWM pin operates in two mutually exclusive modes controlled by SPI register bits 9–11: in current monitor mode, it sources a 1:10,000 scaled replica of OUT1–OUT5 current (±4% accuracy); in PWM input mode, the same pin accepts externally generated PWM signals to set duty cycle for all outputs simultaneously - eliminating need for multiple MCU PWM channels.

Can the L9951XPTR drive inductive loads without external flyback components?

Yes - each half-bridge (OUT1–OUT3) integrates internal bulk-drain diodes (HS-to-VS and LS-to-GND) enabling freewheeling for DC motors and solenoids. High-side drivers (OUT4–OUT5) lack low-side diodes but include ESD protection diodes to GND; external flyback diodes are recommended for highly inductive resistive loads to prevent voltage overshoot beyond VS+11 V rating.

What is the purpose of the CP (charge pump) pin, and how is it used in reverse polarity protection?

The CP pin delivers 6–13 V (depending on VS) to drive the gate of an external N-channel MOSFET placed in the battery feed path. When VS is reversed, the MOSFET remains off, blocking current - achieving reverse polarity protection with <0.05 V forward drop versus ~0.4 V for Schottky diodes. This improves efficiency and thermal performance in always-connected automotive systems.