SLWS237A November   2012  – November 2014 DRV11873

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3  Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 Handling Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Speed Control
      2. 8.3.2  Frequency Generator
      3. 8.3.3  FS Setting
      4. 8.3.4  Lock Protection and RD Output
      5. 8.3.5  Reverse Spin Control FR
      6. 8.3.6  5-V LDO
      7. 8.3.7  Overcurrent Protection
      8. 8.3.8  UVLO
      9. 8.3.9  Thermal Shutdown
      10. 8.3.10 Anti-Voltage Surge (AVS)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Startup
      2. 8.4.2 Closed Loop Control
      3. 8.4.3 AVS Protection
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Trademarks
    2. 12.2 Electrostatic Discharge Caution
    3. 12.3 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component specification, and TI does not warrant its accuracy or completeness. TI’s customers are responsible for determining suitability of components for their purposes. Customers should validate and test their design implementation to confirm system functionality.

9.1 Application Information

DRV11873 only requires five external components. The device needs a 10-µF or higher ceramic capacitor connected to VCC and ground for decoupling. During layout, the strategy of ground copper pour is very important to enhance the thermal performance. For two or more layers, use eight thermal vias. Refer to Layout Example for an example of the PCB layout. For high current motors, place three Schottky diodes between phases U, V, W, and ground. Each diode anode terminal must be connected to ground and the cathode terminal must be connected to either U, V, or W. If there is no COM pin on the motor, one can be simulated. Use three resistors connected in a wye formation, one connected to U, one to V, and one to W. Connect the resistor ends opposite of the phases together. This center point is COM. To find the proper resistor value, start with a value of 10 kΩ and continue to decrease by 1 kΩ until the motor runs properly.

9.2 Typical Application

typ_app_lws237.gifFigure 13. Typical Application Schematic

9.2.1 Design Requirements

Table 1. Design Parameters

MIN TYP MAX UNIT
Motor voltage 5 16 V
VCC capacitor Place as close to the pin as possible 10 µF
Operating current Running with normal load at rated speed 1.5 A
Absolute max current During startup and locked motor condition 2 A

9.2.2 Detailed Design Procedure

  1. Refer to the Design Requirements and ensure the system meets the recommended application range.
    • Ensure the VCC level is in between 5 and 16 V
    • Verify the motor needs no more than 1.5 A during runtime
  2. Follow the application and Power Supply Recommendations when constructing the schematic.
    • If the motor is high current/ high speed, use three Schottky diodes between the phases and ground.
    • Make sure there is adequate capacitance on VCC, V5, VCP, CPP, and CPN.
    • Size the resistor on CS according to the details given in feature description.
    • Use a pull-up on FG and RD.
    • If the motor doesn’t have a common pin, create one using the method listed in Application Information.
  3. Build the hardware according to the Layout Guidelines.
    • Place the supply capacitors as close to the pins as possible.
    • Route the U, V, W, and VCC traces to handle the allowed current.
    • Ensure GND connections are made with the pin and thermal PAD.
    • Use vias on the thermal pad to dissipate heat away from the IC.
  4. Test the system with the application's motor to verify proper operation.

9.2.3 Application Curves

wave_startup_lws237.gifFigure 14. Startup Waveforms
wave_AVS_protect_lws237.gifFigure 16. AVS Protection
wave_lock_detect_lws237.gifFigure 15. Lock Detection