SLVSC40H June   2013  – May 2020 DRV8711

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
  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 SPI Timing Requirements
    7. 6.7 Indexer Timing Requirements
    8. 6.8 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  PWM Motor Drivers
      2. 7.3.2  Direct PWM Input Mode
      3. 7.3.3  Microstepping Indexer
      4. 7.3.4  Current Regulation
      5. 7.3.5  Decay Modes
      6. 7.3.6  Blanking Time
      7. 7.3.7  Predrivers
      8. 7.3.8  Configuring Predrivers
      9. 7.3.9  External FET Selection
      10. 7.3.10 Stall Detection
        1. 7.3.10.1 Internal Stall Detection
        2. 7.3.10.2 External Stall Detection
      11. 7.3.11 Protection Circuits
        1. 7.3.11.1 Overcurrent Protection (OCP)
        2. 7.3.11.2 Predriver Fault
        3. 7.3.11.3 Thermal Shutdown (TSD)
        4. 7.3.11.4 Undervoltage Lockout (UVLO)
    4. 7.4 Device Functional Modes
      1. 7.4.1 RESET and SLEEPn Operation
      2. 7.4.2 Microstepping Drive Current
    5. 7.5 Programming
      1. 7.5.1 Serial Data Format
    6. 7.6 Register Maps
      1. 7.6.1 Control Registers
      2. 7.6.2 CTRL Register (Address = 0x00)
      3. 7.6.3 TORQUE Register (Address = 0x01)
      4. 7.6.4 OFF Register (Address = 0x02)
      5. 7.6.5 BLANK Register (Address = 0x03)
      6. 7.6.6 DECAY Register (Address = 0x04)
      7. 7.6.7 STALL Register (Address = 0x05)
      8. 7.6.8 DRIVE Register (Address = 0x06)
      9. 7.6.9 STATUS Register (Address = 0x07)
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Sense Resistor
      2. 8.1.2 Optional Series Gate Resistor
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Set Step Rate
        2. 8.2.2.2 Calculate Current Regulation
        3. 8.2.2.3 Support External FETs
        4. 8.2.2.4 Pick Decay Mode
        5. 8.2.2.5 Config Stall Detection
        6. 8.2.2.6 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  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

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

8.1.1 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 peak motor current is 3 A, RMS motor current is 2 A, and a 0.05-Ω sense resistor is used, the resistor will dissipate 2 A2 × 0.05 Ω = 0.2 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.