SLVSD19A June   2015  – July 2015 DRV8881

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      DRV8881E Simplified System Diagram
      2.      DRV8881P Simplified System Diagram
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
    2.     DRV8881E PH/EN Pin Functions
    3.     DRV8881P PWM Pin Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagrams
    3. 7.3 Feature Description
      1. 7.3.1  Motor Driver Current Ratings
        1. 7.3.1.1 Peak Current Rating
        2. 7.3.1.2 RMS Current Rating
        3. 7.3.1.3 Full-Scale Current Rating
      2. 7.3.2  PWM Motor Drivers
      3. 7.3.3  Bridge Control
      4. 7.3.4  Current Regulation
      5. 7.3.5  Decay Modes
        1. 7.3.5.1 Mode 1: Slow Decay
        2. 7.3.5.2 Mode 2: Fast Decay
        3. 7.3.5.3 Mode 3: 30%/70% Mixed Decay
      6. 7.3.6  Smart tune
      7. 7.3.7  Adaptive Blanking Time
      8. 7.3.8  Parallel Mode
      9. 7.3.9  Charge Pump
      10. 7.3.10 LDO Voltage Regulator
      11. 7.3.11 Logic and Tri-Level Pin Diagrams
      12. 7.3.12 Protection Circuits
        1. 7.3.12.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.12.2 VCP UVLO (CPUV)
        3. 7.3.12.3 Overcurrent Protection (OCP)
        4. 7.3.12.4 Thermal Shutdown (TSD)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 DRV8881P Typical Application
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Current Regulation
          2. 8.2.1.2.2 Stepper Motor Speed
          3. 8.2.1.2.3 Decay Modes
          4. 8.2.1.2.4 Sense Resistor
        3. 8.2.1.3 Application Curve
      2. 8.2.2 Alternate Application
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Current Regulation
        3. 8.2.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance Sizing
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.6 Smart tune

Smart tune is available on DRV8881E only.

To enable the smart tune mode, pull the ATE pin logic high. Ensure the xDECAY pins are logic low. The smart tune mode is registered internally when exiting from sleep mode or the power-up sequence. The ATE pin can be shorted to V3P3 to pull it logic high for this purpose.

Smart tune greatly simplifies the decay mode selection by automatically configuring the decay mode between slow, mixed, and fast decay. In mixed decay, smart tune dynamically adjusts the fast decay percentage of the total mixed decay time. This feature eliminates motor tuning by automatically determining the best decay setting that results in the lowest ripple for the motor.

The decay mode setting is optimized iteratively each PWM cycle. If the motor current overshoots the target trip level, then the decay mode becomes more aggressive (add fast decay percentage) on the next cycle in order to prevent regulation loss. If there is a long drive time to reach the target trip level, the decay mode becomes less aggressive (remove fast decay percentage) on the next cycle in order to operate with less ripple and more efficiently.

Smart tune will automatically adjust the decay scheme based on operating factors like:

  • Motor winding resistance and inductance
  • Motor aging effects
  • Motor dynamic speed and load
  • Motor supply voltage variation
  • Motor back-EMF difference on rising and falling steps
  • Low-current vs. high-current dI/dt