SLOSE48 December   2020 DRV8434A

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 Indexer Timing Requirements
      1. 6.6.1 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 and Decay Mode
        1. 7.3.5.1 Smart tune Ripple Control
        2. 7.3.5.2 Blanking Time
      6. 7.3.6 Charge Pump
      7. 7.3.7 Linear Voltage Regulators
      8. 7.3.8 Logic Level, tri-level and quad-level Pin Diagrams
        1. 7.3.8.1 nFAULT Pin
      9. 7.3.9 Protection Circuits
        1. 7.3.9.1 VM Undervoltage Lockout (UVLO)
        2. 7.3.9.2 VCP Undervoltage Lockout (CPUV)
        3. 7.3.9.3 Overcurrent Protection (OCP)
        4. 7.3.9.4 Stall Detection
        5. 7.3.9.5 Open-Load Detection (OL)
        6. 7.3.9.6 Thermal Shutdown (OTSD)
        7.       Fault Condition Summary
    4. 7.4 Device Functional Modes
      1. 7.4.1 Sleep Mode (nSLEEP = 0)
      2.      43
      3. 7.4.2 Disable Mode (nSLEEP = 1, ENABLE = 0)
      4. 7.4.3 Operating Mode (nSLEEP = 1, ENABLE = Hi-Z/1)
      5. 7.4.4 nSLEEP Reset Pulse
      6.      Functional Modes Summary
  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
    2. 10.2 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

7.1 Overview

The DRV8434A is an integrated motor-driver solution for bipolar stepper motors. The device provides maximum integration by integrating two N-channel power MOSFET H-bridges, current sense resistors and regulation circuitry, and a microstepping indexer. The DRV8434A is capable of supporting a wide supply voltage of 4.5 to 48 V. DRV8434A provides an output current up to 4 A peak, 2.5 A full-scale, or 1.8 A root mean square (rms). The actual full-scale and rms current depends on the ambient temperature, supply voltage, and PCB thermal capability.

The DRV8434A uses an integrated current-sense architecture which eliminates the need for two external power sense resistors, hence saving significant board space, BOM cost, design efforts and reduces significant power consumption. This architecture removes the power dissipated in the sense resistors by using a current mirror approach and using the internal power MOSFETs for current sensing. The current regulation set point is adjusted by the voltage at the VREF pin.

A simple STEP/DIR interface allows for an external controller to manage the direction and step rate of the stepper motor. The internal microstepping indexer can execute high-accuracy micro-stepping without requiring the external controller to manage the winding current level. The indexer is capable of full step, half step, and 1/4, 1/8, 1/16, 1/32, 1/64, 1/128, and 1/256 microstepping. High microstepping contributes to significant audible noise reduction and smooth motion. In addition to a standard half stepping mode, a noncircular half stepping mode is available for increased torque output at higher motor RPM.

The device operates with smart tune ripple control decay mode, which uses a variable off-time, ripple current control scheme to minimize distortion of the motor winding current. The DRV8434A can detect a motor overload stall condition or an end-of-line travel, by detecting back-emf phase shift between rising and falling current quadrants of the motor current. Unlike conventional stall detection algorithms which require an SPI interface, the DRV8434A detects stall using two digital IO and one analog IO pins.

The device integrates a spread spectrum clocking feature for both the internal digital oscillator and internal charge pump. This feature minimizes the radiated emissions from the device. A low-power sleep mode is included which allows the system to save power when not actively driving the motor.