SLOSE70 December   2020 DRV8434S

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1. 5.1 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
      1. 6.7.1 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  Controlling VREF with an MCU DAC
      5. 7.3.5  Current Regulation
      6. 7.3.6  Decay Modes
        1. 7.3.6.1 Slow Decay for Increasing and Decreasing Current
        2. 7.3.6.2 Slow Decay for Increasing Current, Mixed Decay for Decreasing Current
        3. 7.3.6.3 Slow Decay for Increasing Current, Fast Decay for Decreasing current
        4. 7.3.6.4 Mixed Decay for Increasing and Decreasing Current
        5. 7.3.6.5 Smart tune Dynamic Decay
        6. 7.3.6.6 Smart tune Ripple Control
      7. 7.3.7  PWM OFF Time
      8. 7.3.8  Blanking time
      9. 7.3.9  Charge Pump
      10. 7.3.10 Linear Voltage Regulators
      11. 7.3.11 Logic Level, tri-level and quad-level Pin Diagrams
        1. 7.3.11.1 nFAULT Pin
      12. 7.3.12 Protection Circuits
        1. 7.3.12.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.12.2 VCP Undervoltage Lockout (CPUV)
        3. 7.3.12.3 Overcurrent Protection (OCP)
          1. 7.3.12.3.1 Latched Shutdown (OCP_MODE = 0b)
          2. 7.3.12.3.2 Automatic Retry (OCP_MODE = 1b)
        4. 7.3.12.4 Stall Detection
        5. 7.3.12.5 Open-Load Detection (OL)
        6. 7.3.12.6 Overtemperature Warning (OTW)
        7. 7.3.12.7 Thermal Shutdown (OTSD)
          1. 7.3.12.7.1 Latched Shutdown (OTSD_MODE = 0b)
          2. 7.3.12.7.2 Automatic Recovery (OTSD_MODE = 1b)
        8.       Fault Condition Summary
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode (nSLEEP = 0)
      2.      56
      3. 7.4.2 Disable Mode (nSLEEP = 1, ENABLE = 0)
      4. 7.4.3 Operating Mode (nSLEEP = 1, ENABLE = 1)
      5. 7.4.4 nSLEEP Reset Pulse
      6.      Functional Modes Summary
    5. 7.5 Programming
      1. 7.5.1 Serial Peripheral Interface (SPI) Communication
        1. 7.5.1.1 SPI Format
        2. 7.5.1.2 SPI for a Single Target Device
        3. 7.5.1.3 SPI for Multiple Target Devices in Daisy Chain Configuration
        4. 7.5.1.4 SPI for Multiple Target Devices in Parallel Configuration
    6. 7.6 Register Maps
  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 Mode
        4. 8.2.2.4 Application Curves
        5. 8.2.2.5 Thermal Application
          1. 8.2.2.5.1 Power Dissipation
          2. 8.2.2.5.2 Conduction Loss
          3. 8.2.2.5.3 Switching Loss
          4. 8.2.2.5.4 Power Dissipation Due to Quiescent Current
          5. 8.2.2.5.5 Total Power Dissipation
          6. 8.2.2.5.6 Device Junction Temperature Estimation
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support 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

7.3.6.1 Slow Decay for Increasing and Decreasing Current

GUID-4334D770-68BB-42E2-B594-3651198DE9BD-low.gifFigure 7-8 Slow/Slow Decay Mode

During slow decay, both low-side MOSFETs of the H-bridge are turned on, allowing the current to be recirculated.

Slow decay exhibits the least current ripple of the decay modes for a given tOFF. However on decreasing current steps, slow decay will take a long time to settle to the new ITRIP level because the current decreases very slowly. If the current at the end of the off time is above the ITRIP level, slow decay will be extended for multiple off time duration, until the current at the end of the cumulative off time is below the ITRIP level.

When the winding current is held static for a long time (for example when no STEP input is present) or at very low step rates, slow decay may not properly regulate the current because back-EMF will be small or absent across the motor windings. The motor current can rise rapidly, and may require an extremely long off-time to regulate the current. In some cases this could result in loss of current regulation. An aggressive decay mode is recommended in such cases.