STMicroelectronics EVAL-L99SM81VQ

Overview

EVAL-L99SM81VQ from STMicroelectronics is an evaluation board for the L99SM81VQ6 bipolar stepper motor driver IC, enabling micro-stepping control and real-time coil voltage-based stall detection. It comprises a SPC56-based motherboard and a daughterboard hosting the L99SM81VQ6, with configurable 5 V/3.3 V digital supply, integrated 5 V linear regulator output, reverse battery protection (MOSFET or diode jumper option), and ISO pulse protection.

For engineers reviewing the EVAL-L99SM81VQ datasheet, EVAL-L99SM81VQ pinout, EVAL-L99SM81VQ application, or EVAL-L99SM81VQ equivalent, this board supports rapid validation of closed-loop stepper positioning in automotive body electronics, industrial actuators, and precision HVAC dampers using GUI-driven parameter tuning and live fault flag monitoring.

Technical Context

The EVAL-L99SM81VQ implements a complete hardware-software evaluation platform centered on the L99SM81VQ6 - a high-voltage, high-current bipolar stepper driver with integrated current sensing, thermal shutdown, and stall detection via analog coil voltage measurement. The motherboard's SPC56 MCU handles SPI communication, real-time register configuration, and telemetry aggregation.

Power architecture includes dual-supply flexibility (5 V or 3.3 V logic), 12 V main input via daughterboard connector, optional solderable output capacitors at motor terminals, and a dedicated jumper for MOSFET-based reverse polarity protection - replaceable with discrete diodes per design requirement.

Key Specifications

Availability

EVAL-L99SM81VQ is available at Aetrix Electronics and suitable for automotive body control modules, industrial valve actuators, and HVAC damper positioning systems requiring stable component supply and rapid prototyping capability.

Supply support for EVAL-L99SM81VQ 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 specializing in automotive, industrial, and power management solutions, with broad portfolio coverage from microcontrollers to intelligent power drivers.

The EVAL-L99SM81VQ belongs to ST's motor control evaluation platform family, designed specifically to accelerate development of robust, sensorless stepper motion systems for safety-critical and energy-efficient applications.

FAQ

What motor types does the EVAL-L99SM81VQ support?

The board is configured exclusively for bipolar stepper motors, supporting full-, half-, quarter-, and up to 1/256-step micro-stepping modes. It does not support unipolar steppers, brushed DC, or BLDC motors. Motor connection uses standard 4-wire interface routed to terminal blocks on the daughterboard, with current sense feedback enabled for stall detection.

How is communication established between the PC and the evaluation board?

Communication occurs over USB Type-B connection using ST's proprietary GUI software, which maps SPI commands from the SPC56 motherboard MCU to the L99SM81VQ6 registers. The GUI runs on Windows XP/7/8 and displays real-time telemetry including coil voltage, device temperature, supply rail status, and active fault flags without requiring external debug probes.

Can the 5 V linear regulator output be used to power external circuitry?

Yes - the L99SM81VQ6's internal 5 V linear regulator output is accessible via a dedicated connector on the daughterboard and rated for up to 150 mA. It is intended for powering auxiliary sensors or level-shifting circuitry, but must not exceed its specified current limit or operate outside ambient temperature range of –40 °C to 150 °C junction.

Is ISO pulse protection soldered and functional by default?

No - ISO 7637-2 transient protection components are included on the PCB but remain unsoldered per default configuration. Users must manually solder TVS diodes or suppressors at designated footprints to enable compliance with automotive load dump and pulse test requirements; no firmware or jumper setting activates this protection automatically.