Overview
The L99SM81VQ6TR from STMicroelectronics is an advanced, automotive-grade integrated driver designed for bipolar two-phase stepper motors. This device is AEC-Q100 qualified, ensuring its reliability and performance in demanding automotive applications. It features programmable step modes, including full step, half step, mini step, 1/8 micro step, and 1/16 micro step, making it highly versatile for various motor control needs. The L99SM81VQ6TR also includes integrated current sensing and PWM regulation, along with multiple protection and diagnostic features, enhancing its robustness and reliability.
Key Specifications
| Parameter | Description |
|---|---|
| Package | QFN-40-EP (6x6 mm) |
| Current Capability | Up to 1.35 A |
| Step Modes | Full step, Half step, Mini step, 1/8 Micro step, 1/16 Micro step |
| Current Regulation | Integrated PWM control with 10-bit resolution |
| Decay Modes | Slow, Mixed, Auto decay mode 1, Auto decay mode 2 |
| Control Interface | ST SPI 4.1 interface, 3x programmable control pins |
| Voltage Regulator | 5 V low drop voltage regulator, short-circuit protected |
| Standby Current | Typically 10 µA |
| Protection Features | Overvoltage, undervoltage, thermal warning, thermal shutdown, open load, short to battery, short to GND |
Key Features
- AEC-Q100 qualified for automotive applications
- Programmable step modes: full step, half step, mini step, 1/8 micro step, 1/16 micro step
- Integrated current sensing and PWM regulation with 10-bit resolution
- Four programmable decay modes: slow, mixed, auto decay mode 1, auto decay mode 2
- Three programmable control pins for direct control of step clock, direction, hold, and step modes
- Programmable analog output for Tj measurement or band-gap reference
- Two programmable digital outputs for internally generated PWM ON duty cycles, error signals, coils voltage measurement synchronization signals
- Programmable MOSFETs switching speed for EMC and power dissipation optimization
- PWM frequency wobbling for reduction of conducted EM energy
- Integrated ADC for coil voltage measurement and stall detection
- Thermal warning and shutdown
Applications
The L99SM81VQ6TR is designed for various automotive applications, including:
- Adaptive front light systems
- Projectors for head-up displays
- Other bipolar two-phase stepper motor applications requiring precise control and reliability
Q & A
- What is the maximum current capability of the L99SM81VQ6TR?
The L99SM81VQ6TR has a maximum current capability of up to 1.35 A.
- What are the available step modes for the L99SM81VQ6TR?
The device supports full step, half step, mini step, 1/8 micro step, and 1/16 micro step modes.
- How does the L99SM81VQ6TR regulate current?
The device uses integrated PWM control with a 10-bit resolution for current regulation.
- What protection features are included in the L99SM81VQ6TR?
The device includes overvoltage, undervoltage, thermal warning, thermal shutdown, open load, short to battery, and short to GND protections.
- What is the purpose of the ST SPI 4.1 interface in the L99SM81VQ6TR?
The ST SPI 4.1 interface allows for control and diagnostics of the device, enabling the adjustment of device parameters and the reading of diagnostic information.
- How does the L99SM81VQ6TR handle standby mode?
In standby mode, the device's voltage regulator, charge pump, and all outputs are turned off, and the registers are set to their default values.
- What is the role of the charge pump in the L99SM81VQ6TR?
The charge pump is used to generate the necessary voltage for the device's operation and can be modulated with a wobble frequency generator to optimize EMC performance.
- How does the L99SM81VQ6TR measure coil voltage for stall detection?
The device uses an integrated ADC to measure coil voltage for stall detection.
- What is the typical standby current consumption of the L99SM81VQ6TR?
The typical standby current consumption is 10 µA.
- Is the L99SM81VQ6TR suitable for automotive applications?
Yes, the L99SM81VQ6TR is AEC-Q100 qualified, making it suitable for automotive applications.
