SLES242G December   2009  – December 2014 DRV8412

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Simplified Application Diagram
  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 Package Heat Dissipation Ratings
    6. 6.6 Package Power Deratings (DRV8412)
    7. 6.7 Electrical Characteristics
    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 Error Reporting
      2. 7.3.2 Device Protection System
        1. 7.3.2.1 Bootstrap Capacitor Undervoltage Protection
        2. 7.3.2.2 Overcurrent (OC) Protection
        3. 7.3.2.3 Overtemperature Protection
        4. 7.3.2.4 Undervoltage Protection (UVP) and Power-On Reset (POR)
      3. 7.3.3 Device Reset
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Full Bridge Mode Operation
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Motor Voltage
          2. 8.2.1.2.2 Current Requirement of 12-V Power Supply
          3. 8.2.1.2.3 Voltage of Decoupling Capacitor
          4. 8.2.1.2.4 Overcurrent Threshold
          5. 8.2.1.2.5 Sense Resistor
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Parallel Full Bridge Mode Operation
      3. 8.2.3 Stepper Motor Operation
      4. 8.2.4 TEC Driver
      5. 8.2.5 LED Lighting Driver
  9. 9 Power Supply Recommendations
    1. 9.1 Bulk Capacitance
    2. 9.2 Power Supplies
    3. 9.3 System Power-Up and Power-Down Sequence
      1. 9.3.1 Powering Up
      2. 9.3.2 Powering Down
    4. 9.4 System Design Recommendations
      1. 9.4.1 VREG Pin
      2. 9.4.2 VDD Pin
      3. 9.4.3 OTW Pin
      4. 9.4.4 Mode Select Pin
      5. 9.4.5 Parallel Mode Operation
      6. 9.4.6 TEC Driver Application
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 PCB Material Recommendation
      2. 10.1.2 Ground Plane
      3. 10.1.3 Decoupling Capacitor
      4. 10.1.4 AGND
    2. 10.2 Layout Example
      1. 10.2.1 Current Shunt Resistor
    3. 10.3 Thermal Considerations
      1. 10.3.1 DRV8412 Thermal Via Design Recommendation
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.3 Thermal Considerations

The thermally enhanced package provided with the DRV8432 is designed to interface directly to heat sink using a thermal interface compound, (for example, Ceramique from Arctic Silver, TIMTronics 413, and so forth). The heat sink then absorbs heat from the ICs and couples it to the local air. It is also a good practice to connect the heatsink to system ground on the PCB board to reduce the ground noise.

RθJA is a system thermal resistance from junction to ambient air. As such, it is a system parameter with the following components:

  • RθJC (the thermal resistance from junction to case, or in this example the power pad or heat slug)
  • Thermal grease thermal resistance
  • Heat sink thermal resistance

The thermal grease thermal resistance can be calculated from the exposed power pad or heat slug area and the thermal grease manufacturer's area thermal resistance (expressed in °C-in2/W or °C-mm2/W). The approximate exposed heat slug size is as follows:

  • DRV8432, 36-pin PSOP3 …… 0.124 in2 (80 mm2)

The thermal resistance of thermal pads is considered higher than a thin thermal grease layer and is not recommended. Thermal tape has an even higher thermal resistance and should not be used at all. Heat sink thermal resistance is predicted by the heat sink vendor, modeled using a continuous flow dynamics (CFD) model, or measured.

Thus the system RθJA = RθJC + thermal grease resistance + heat sink resistance.

See the TI application report, IC Package Thermal Metrics (SPRA953), for more thermal information.