STMicroelectronics EVAL-L99SM81VY

Overview

EVAL-L99SM81VY from STMicroelectronics is an evaluation board for the L99SM81V bipolar stepper motor driver IC, enabling micro-stepping control and coil voltage-based stall detection. It comprises a SPC56-based motherboard and a daughterboard hosting the L99SM81V, with configurable 5 V/3.3 V digital supply, reverse-battery MOSFET protection, and ISO pulse protection (not soldered).

For engineers reviewing the EVAL-L99SM81VY datasheet, EVAL-L99SM81VY pinout, EVAL-L99SM81VY application, or EVAL-L99SM81VY equivalent, this board supports rapid validation of L99SM81V in automotive HVAC actuators, industrial valve positioning, and precision motion control systems requiring real-time fault flag monitoring and junction temperature feedback.

Technical Context

The board implements a dual-board architecture: the motherboard handles SPI communication, fault logging, and power sequencing via an SPC56 MCU, while the daughterboard integrates the L99SM81V with dedicated current-sense resistors, output capacitor pads, and a jumper-configurable 5 V linear regulator output. It supports standby mode and real-time telemetry including motor coil voltage, main supply voltage, and thermal status.

USB Type-B connectivity enables GUI-driven parameter configuration (e.g., micro-step resolution, decay mode, overcurrent threshold) and live data streaming-no external logic analyzer or custom firmware required. The jumper-selectable digital supply ensures compatibility with both 3.3 V and 5 V host controller interfaces.

Key Specifications

Availability

EVAL-L99SM81VY is available at Aetrix Electronics and suitable for automotive HVAC actuator development, industrial valve positioning systems, and precision motion control prototyping requiring stable component supply and validated reference hardware.

Supply support for EVAL-L99SM81VY 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, designing and manufacturing analog, MCU, power, and sensor solutions for automotive, industrial, and consumer applications.

The EVAL-L99SM81VY belongs to ST's motor control evaluation platform family, engineered to accelerate adoption of their automotive-qualified smart power drivers like the L99SM81V in safety-critical motion systems.

FAQ

Does EVAL-L99SM81VY support real-time stall detection?

Yes. The board enables stall detection by measuring voltage across motor coils during current decay phases-this analog signal is routed to the SPC56 MCU for real-time analysis and flag generation without external ADC hardware.

What software tools are required to operate EVAL-L99SM81VY?

The official ST-provided GUI software-downloadable from st.com-runs on Windows XP/7/8 and communicates via USB Type-B. It provides full register access, live telemetry display (junction temperature, supply voltage, fault flags), and micro-step configuration without coding.

Can the 12 V input be replaced with another voltage source?

No-the daughterboard is designed for 12 V nominal input per automotive standards. Substituting with lower or higher voltages risks damaging the L99SM81V's internal regulators and gate drivers, as confirmed by DB3812 schematic and layout constraints.

Is the ISO pulse protection circuit pre-assembled on the board?

No. The ISO 7637-2 transient protection circuit is included in the schematic but not populated on the PCB-users must solder discrete components if required for specific EMC test compliance, as stated in DB3812 Rev 1 page 2.