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STMicroelectronics L99SM81VYTR
- Part No.:
- L99SM81VYTR
- Manufacturer:
- STMicroelectronics
- Category:
- Motor Drivers, Controllers
- Package:
- 36-PowerFSOP (0.295", 7.50mm Width)
- Datasheet:
-
L99SM81VYTR.pdf
- Description:
- STEPPER MOTOR DRIVER
- Quantity:
- Payment:
- Shipping:
Inventory:1,765
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Product details
Overview
L99SM81VYTR from STMicroelectronics is an AEC-Q100 qualified automotive bipolar 2-phase stepper motor driver with programmable micro-stepping (up to 1/16), integrated PWM current regulation (1.35 A max), stall detection via coil voltage ADC, and ST SPI 4.1 interface for diagnostics and configuration - used in adaptive front lighting and head-up display projectors.
For engineers reviewing the L99SM81VYTR datasheet, L99SM81VYTR pinout, L99SM81VYTR application, or L99SM81VYTR equivalent, key selection criteria include micro-step resolution (1/16), dual-mode current programming (RUN/HOLD), decay mode flexibility (4 options), thermal warning/shutdown, and integrated 5 V regulator for sensor supply.
Technical Context
The device implements a closed-loop current control architecture using integrated high-side/low-side MOSFETs, a 6-bit DAC for reference current generation, and two independent 4-bit full-scale amplitude settings for RUN and HOLD modes - enabling precise torque management across motion phases. Its stall detection relies on synchronized 4-point coil voltage sampling (0°, 90°, 180°, 270°) processed by an internal ADC with configurable low/high limits.
Control is executed via ST SPI 4.1 (4-wire, CPOL=0, CPHA=0), supporting register read/write, global/motor status reporting, and real-time diagnostics including open-load, overcurrent, and thermal faults. Digital I/Os (CTRL1–CTRL3, ERR, EC, PWM, CVRDY) allow direct step/direction/HOLD control and hardware-triggered diagnostics without host intervention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Max Output Current | 1.35 A per phase - supports NEMA17-class motors in automotive ADAS actuators |
| Micro-step Resolution | 1/16 micro-stepping - enables smooth, low-vibration positioning in optical alignment systems |
| Current Regulation | Equivalent 10-bit resolution (6-bit DAC + dual 4-bit amplitude) - allows fine-grained torque tuning in RUN vs HOLD |
| Decay Modes | 4 programmable modes: slow, mixed, auto-decay-1, auto-decay-2 - optimizes torque ripple and power dissipation per load condition |
| Stall Detection | Integrated ADC with 4-phase coil voltage sampling and programmable thresholds - detects rotor lock without external sensors |
| Supply Regulator | 5 V LDO (short-circuit protected) - powers external Hall sensors or microcontrollers in same subsystem |
| Standby Current | 10 µA typical - enables always-on readiness in low-power automotive domains |
Pinout & Package
Available in PowerSSO-36 (exposed pad, thermally enhanced) and QFN40L packages. This part number (L99SM81VYTR) corresponds to the PowerSSO-36 variant per ST order code documentation (Y = PowerSSO-36, TR = tape & reel).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| VS | Main power supply input | Connects to 5.5–28 V automotive battery rail; feeds H-bridge and charge pump |
| VREG | Charge pump supply | Provides gate drive voltage for high-side MOSFETs; requires local 100 nF decoupling |
| VDD | Digital logic supply | 3.3 V nominal supply for SPI interface, registers, and control logic |
| EN | Enable input | Active-high digital enable; places device in ultra-low-power standby (<10 µA) when low |
| STEP, DIR, SMODE | Direct control inputs | Hardware-controlled stepping clock, direction, and step mode selection - bypasses SPI for basic motion |
| OUTA1/OUTA2/OUTB1/OUTB2 | H-bridge outputs | Drive bipolar stepper motor coils A and B; each pair forms one full bridge |
| SCK/SDI/SDO/CSN | SPI interface | ST SPI 4.1 compliant (CPOL=0, CPHA=0); supports daisy-chaining and diagnostic burst reads |
| AOUT | Analog output | Configurable as junction temperature monitor or bandgap reference (1.22 V) |
| DOUT1/DOUT2 | Digital outputs | Programmable signals: error flags, PWM duty cycle, CVRDY sync pulses, or coil voltage alerts |
Key Features
| Feature | Design Value |
|---|---|
| PWM frequency wobbling | Reduces peak conducted EMI by spreading switching energy across 10 kHz bandwidth - meets CISPR 25 Class 5 |
| Programmable MOSFET slew rate | Four selectable switching speeds - balances EMC compliance against power loss and dv/dt stress on motor windings |
| Integrated cross-current protection | Hardware dead-time insertion prevents shoot-through during H-bridge commutation - eliminates need for external timing circuits |
| Coil voltage measurement synchronization | Hardware-triggered sampling at precise electrical angles (0°/90°/180°/270°) - ensures repeatable stall detection under varying speed/load |
| Thermal warning & shutdown | Two-stage thermal response: warning flag at 150 °C, automatic shutdown at 175 °C - protects silicon and motor during overload |
Applications
| Adaptive Front Lighting System (AFS) | Head-Up Display (HUD) Projector |
|---|---|
Use Scenario: Horizontal and vertical beam steering of LED matrix headlights in response to vehicle speed, steering angle, and road geometry. IC Role / Device Role / Timing Role: Bipolar stepper driver controlling lens positioners with 1/16 micro-stepping and stall detection to prevent mechanical jamming. Use Value: Enables sub-milliradian angular resolution and failsafe stall recovery without position sensors - critical for ISO 16750-2 vibration environments. | Use Scenario: Precision focus and tilt adjustment of MEMS mirror or LCD panel in automotive HUD units. IC Role / Device Role / Timing Role: Closed-loop current-controlled stepper actuator with integrated 5 V regulator powering position feedback circuitry. Use Value: Eliminates external LDO and reduces BOM count while maintaining ±0.5% current accuracy across -40°C to 150°C ambient. |
| Electric Power Steering (EPS) Assist Module | Automotive HVAC Airflow Control |
Use Scenario: Auxiliary damping or return-to-center actuation in column-assist EPS systems during fault conditions. IC Role / Device Role / Timing Role: Safety-redundant stepper driver with AEC-Q100 Grade 0 qualification and SPI-accessible diagnostic registers. Use Value: Supports ASIL-B decomposition via hardware-level fault detection (open load, short to battery/GND, thermal) and CRC-protected SPI communication. | Use Scenario: Motorized blend door and mode door positioning in climate control systems. IC Role / Device Role / Timing Role: Low-quiescent-current (10 µA) stepper controller enabling always-on HVAC responsiveness after ignition-off. Use Value: Reduces system sleep current below 20 µA threshold required for 30-day parking battery drain compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bipolar stepper motor driver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TMC2130-LA | Integrated stealthChop™ silent stepping; no built-in 5 V regulator; SPI interface only (no direct STEP/DIR pins) | Targeted at noise-sensitive cabin applications; lacks automotive-grade diagnostics and AEC-Q100 qualification | Select if acoustic performance > functional safety; verify external 5 V supply and diagnostic coverage |
| DRV8889-Q1 | Higher current (2.5 A), but fixed 1/8 micro-stepping only; no stall detection ADC; uses standard SPI (not ST SPI 4.1) | Used in larger-aperture optical systems; requires external voltage monitor and thermal sensor for full fault coverage | Select for higher torque demand where micro-step granularity and integrated stall detection are secondary |
Compared with TMC2130-LA and DRV8889-Q1, L99SM81VYTR uniquely combines AEC-Q100 qualification, on-chip stall detection with angle-synchronized sampling, dual-mode current programming, and a safety-certifiable 5 V regulator - making it optimal for ASIL-B decomposable automotive motion control.
Availability
L99SM81VYTR is available at Aetrix Electronics and suitable for adaptive front lighting systems, head-up display projectors, and HVAC airflow control modules requiring stable component supply, automotive qualification, and long-term lifecycle support.
Supply support for L99SM81VYTR 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, designing and manufacturing analog, MCU, power, and automotive ICs with vertical fabrication capability.
L99SM81VYTR belongs to ST's automotive power driver product line, engineered specifically for functional-safety-compliant stepper actuation in ADAS, lighting, and body electronics - emphasizing integrated diagnostics, EMC robustness, and extended temperature operation.
FAQ
What is the maximum motor supply voltage supported by L99SM81VYTR?
The L99SM81VYTR supports VS input from 5.5 V to 28 V DC, covering 12 V and 24 V automotive battery systems with transient tolerance up to 40 V (per absolute maximum ratings). Operation above 28 V risks permanent damage; external TVS clamping is recommended for load-dump protection.
Does L99SM81VYTR require external current sense resistors?
No. The device uses fully integrated current sensing with no external shunt resistors required. Current regulation is achieved via internal MOSFET RDS(on) monitoring and PWM duty-cycle adjustment, delivering equivalent 10-bit resolution without board space or power loss penalties.
How does stall detection work without position encoders?
Stall detection uses the integrated ADC to measure back-EMF-induced coil voltage at four precise electrical angles. When rotor stalls, voltage amplitude collapses below programmable MCVLLA/B thresholds. Detection is hardware-automated and reported via SPI status register MSR bit 4 (STALL_DET) within 100 µs of event occurrence.
Can L99SM81VYTR operate in standalone mode without SPI communication?
Yes. Direct control pins (STEP, DIR, SMODE, EN) allow full micro-stepping operation without SPI. All step modes, current amplitudes, and decay settings default to factory-programmed values on power-up, enabling immediate motion initiation in fail-safe or boot-time scenarios.
L99SM81VYTR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- STMicroelectronics
- Series:
- -
- Package/Case:
- 36-PowerFSOP (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Motor Type - Stepper:
- Bipolar
- Motor Type - AC, DC:
- -
- Function:
- Driver
- Output Configuration:
- Half Bridge (2)
- Interface:
- PWM, SPI
- Technology:
- Power MOSFET
- Step Resolution:
- 1, 1/2, 1/4, 1/8, 1/16
- Applications:
- -
- Current - Output:
- 1.35A
- Voltage - Supply:
- 6V ~ 28V
- Voltage - Load:
- 5V
- Operating Temperature:
- -40°C ~ 150°C (TJ)
- Grade:
- Automotive
- Qualification:
- AEC-Q100
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- PowerSSO-36
L99SM81VYTR FAQ
1.How can I place an order for L99SM81VYTR through Aetrix?
Please submit a Request for Quotation (RFQ) for L99SM81VYTR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for L99SM81VYTR reliable?
The price and inventory of L99SM81VYTR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for L99SM81VYTR is usually 5 days.
3.What payment methods are accepted for L99SM81VYTR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for L99SM81VYTR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for L99SM81VYTR?
L99SM81VYTR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your L99SM81VYTR order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for L99SM81VYTR?
For technical support, including L99SM81VYTR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your L99SM81VYTR requirements.
6.How does Aetrix verify that L99SM81VYTR is sourced from the original manufacturer or authorized distributors?
All L99SM81VYTR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that L99SM81VYTR meets industry standards.
7.What is the process for return or replacement of L99SM81VYTR?
All L99SM81VYTR units undergo pre-shipment inspection (PSI). If there is an issue with L99SM81VYTR, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The L99SM81VYTR part is unused and in its original packaging.
Return procedure for L99SM81VYTR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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