STMicroelectronics L9958XP

Overview

L9958XP from STMicroelectronics is a SPI-controlled H-bridge IC designed for DC and stepper motor control in safety-critical automotive and industrial applications. It features programmable current regulation up to 8.6 A (typ.), operates from 4.0 V to 28 V battery supply, integrates overtemperature and short-circuit protection, and supports daisy-chain SPI diagnostics. Its PowerSSO24 package enables compact placement in space-constrained motor driver modules.

For engineers reviewing the L9958XP datasheet, L9958XP pinout, L9958XP application, or L9958XP equivalent, key selection criteria include its 16-bit SPI diagnostic interface, ±10% current regulation accuracy with external reference resistor, tristate fail-safe behavior on fault, and dual ground (PGND/GND) layout requirements for EMI-sensitive motor drive systems.

Technical Context

The L9958XP implements a fully protected half-bridge output stage with integrated freewheeling diodes and active low-side MOSFET switching during freewheeling to reduce power dissipation. Its control logic decodes DIR/PWM/EN/DI inputs to configure forward, reverse, or freewheeling states while enforcing tristate on any fault or disable condition.

SPI communication uses 16-bit frames for configuration (CFG_REG) and diagnostics (DIA_REG), enabling real-time monitoring of short-to-battery, short-to-ground, open-load (ON-state), overtemperature, and supply faults. Daisy-chain capability allows multi-device synchronization without additional GPIO overhead.

Key Specifications

Pinout & Package

The L9958XP is housed in the PowerSSO24 package (JEDEC MO271A), featuring an exposed thermal slug soldered to PCB GND for enhanced thermal performance. It separates logic ground (GND, pin 22) and power ground (PGND, pin 11), requiring local shorting near the IC to minimize ground bounce and EMI.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar H-bridge motor driver applications.

Compared with DRV8876PWPR and VNH7040ASTR, the L9958XP uniquely delivers integrated full H-bridge operation with SPI-based per-channel diagnostics and fail-safe tristate-all in a single PowerSSO24 package-making it optimal for ASIL-B-compliant automotive and industrial motion control where functional safety and board space are constrained.

Availability

L9958XP is available at Aetrix Electronics and suitable for electric power steering, automotive HVAC systems, industrial linear actuators, and medical infusion pumps requiring stable component supply across extended temperature and voltage ranges.

Supply support for L9958XP 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 manufacturing and quality certifications including AEC-Q100 and ISO/TS 16949.

The L9958XP belongs to ST's L99 family of automotive-grade motor drivers, engineered specifically for safety-critical DC and stepper motor control under extreme environmental conditions-including extended temperature operation and harsh electrical transients.

FAQ

What is the purpose of separating PGND and GND in the L9958XP PowerSSO24 package?

The L9958XP separates PGND (pin 11) and GND (pin 22) to isolate high-current power return paths from sensitive logic and SPI signal references. This reduces ground bounce and EMI coupling during high dI/dt motor switching. ST mandates local shorting of these pins near the IC on the PCB to maintain low-impedance return while preserving noise isolation-critical for reliable SPI communication and accurate diagnostics in automotive environments.

How does the L9958XP handle freewheeling current, and why is it different from standard diode-based freewheeling?

The L9958XP actively switches the low-side MOSFET ON during freewheeling instead of relying solely on the body diode. This reduces conduction loss by lowering the effective voltage drop from ~0.7 V (diode) to ~0.15 V (MOSFET R_DS(on)), cutting power dissipation by ~30%. The feature is automatic and transparent to the user-no SPI configuration required-and improves thermal efficiency in continuous PWM operation.

Can the L9958XP operate with a 3.3 V microcontroller SPI interface?

Yes-the L9958XP supports 3.3 V CMOS-compatible SPI signaling on SI, SO, SCK, and CS lines when VDDIO (pin 4) is supplied with 3.3 V. Its digital inputs tolerate 3.3 V and 5 V logic levels, and the SPI interface remains fully functional across both voltage domains. However, VDDIO must be externally regulated to 3.3 V or 5 V; it is not internally generated.

What happens to the outputs during a VDD undervoltage event?

When VDD drops below its undervoltage lockout threshold (~4.25 V typ.), the L9958XP disables all output stages and forces OUT1 and OUT2 into high-impedance tristate. SPI communication remains active if VDDIO is still valid, allowing the host MCU to read the "VDD_UV" flag in the diagnostic register (DIA_REG bit 10). This ensures safe motor coasting and preserves fault visibility during brownout conditions.