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

8.2.2.4 Sense Resistor

For optimal performance, it is important for the sense resistor to be:

  • Surface-mount
  • Low inductance
  • Rated for high enough power
  • Placed closely to the motor driver

The power dissipated by the sense resistor equals Irms2 × R. For example, if the rms motor current is 1.4A and a 250 mΩ sense resistor is used, the resistor will dissipate 1.4 A2 × 0.25 Ω = 0.49 W. The power quickly increases with higher current levels.

Resistors typically have a rated power within some ambient temperature range, along with a derated power curve for high ambient temperatures. When a PCB is shared with other components generating heat, margin should be added. It is always best to measure the actual sense resistor temperature in a final system, along with the power MOSFETs, as those are often the hottest components.

Because power resistors are larger and more expensive than standard resistors, it is common practice to use multiple standard resistors in parallel, between the sense node and ground. This distributes the current and heat dissipation.