SLVSD18C June   2015  – August 2017 DRV8880

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified System Diagram
      2.      Microstepping Current Waveform
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     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 Indexer Timing Requirements
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Stepper 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  Microstepping Indexer
      4. 7.3.4  Current Regulation
      5. 7.3.5  Decay Modes
        1. 7.3.5.1 Mode 1: Slow Decay for Increasing and Decreasing Current
        2. 7.3.5.2 Mode 2: Slow Decay for Increasing Current, Mixed Decay for Decreasing current
        3. 7.3.5.3 Mode 3: Mixed Decay for Increasing and Decreasing Current
        4. 7.3.5.4 Mode 4: Slow Decay for Increasing Current, Fast Decay for Decreasing current
        5. 7.3.5.5 Mode 5: Fast Decay for Increasing and Decreasing Current
      6. 7.3.6  Smart Tune
      7. 7.3.7  Adaptive Blanking Time
      8. 7.3.8  Charge Pump
      9. 7.3.9  LDO Voltage Regulator
      10. 7.3.10 Logic and Tri-Level Pin Diagrams
      11. 7.3.11 Power Supplies and Input Pins
      12. 7.3.12 Protection Circuits
      13. 7.3.13 VM UVLO (UVLO2)
      14. 7.3.14 Logic Undervoltage (UVLO1)
      15. 7.3.15 VCP Undervoltage Lockout (CPUV)
      16. 7.3.16 Thermal Shutdown (TSD)
      17. 7.3.17 Overcurrent Protection (OCP)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Stepper Motor Speed
        2. 8.2.2.2 Current Regulation
        3. 8.2.2.3 Decay Modes
        4. 8.2.2.4 Sense Resistor
      3. 8.2.3 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 Receiving Notification of Documentation Updates
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • RHR|28
  • PWP|28
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.5.2 Mode 2: Slow Decay for Increasing Current, Mixed Decay for Decreasing current

DRV8880 mode2_lvsd18.gifFigure 17. Slow/Mixed Decay Mode

Mixed decay begins as fast decay for a time, followed by slow decay for the remainder of tOFF. In this mode, mixed decay only occurs during decreasing current. Slow decay is used for increasing current.

This mode exhibits the same current ripple as slow decay for increasing current, since for increasing current, only slow decay is used. For decreasing current, the ripple is larger than slow decay, but smaller than fast decay. On decreasing current steps, mixed decay will settle to the new ITRIP level faster than slow decay.

In cases where current is held for a long time (no input in the STEP pin) 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 may require a large off-time. In some cases this may cause a loss of current regulation, and a more aggressive decay mode is recommended.