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

7.3.5.3 Mode 3: 30%/70% Mixed Decay

To configure the DRV8881 into this mode, pull DECAY1 logic high and pull DECAY0 logic low.

DRV8881 tim_30_70_decay_lvsd19.gifFigure 18. Mixed Decay Mode (30% Fast, 70% Slow)

Mixed decay begins as fast decay for 30% of tOFF, followed by slow decay for the remainder of tOFF. In this mode, mixed decay occurs for both increasing and decreasing current steps.

This mode exhibits ripple larger than slow decay, but smaller than fast decay. Mixed decay will settle to the new ITRIP level faster than slow decay when dealing with decreasing current trip levels.

In cases where current is held for a long time or at very-low stepping speeds, slow decay may not properly regulate current because no back-EMF is present across the motor windings. In this state, motor current can rise very quickly, and requires an excessively large off-time. Increasing/decreasing mixed decay mode allows the current level to stay in regulation when no back-EMF is present across the motor windings.