SLVSD29 October   2015 DRV8704

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 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 (Dual Brushed DC Gate Driver)
      3. 7.3.3  Current Regulation
      4. 7.3.4  Decay Modes
      5. 7.3.5  Blanking Time
      6. 7.3.6  Gate Drivers
      7. 7.3.7  Configuring Gate Drivers
      8. 7.3.8  External FET Selection
      9. 7.3.9  Protection Circuits
        1. 7.3.9.1 Overcurrent Protection (OCP)
        2. 7.3.9.2 Gate Driver Fault (PDF)
        3. 7.3.9.3 Thermal Shutdown (TSD)
        4. 7.3.9.4 Undervoltage Lockout (UVLO)
      10. 7.3.10 Serial Data Format
    4. 7.4 Device Functional Modes
    5. 7.5 Register Maps
      1. 7.5.1 Control Registers
        1. 7.5.1.1 CTRL Register (Address = 0x00h)
          1. Table 4. CTRL Register
        2. 7.5.1.2 TORQUE Register (Address = 0x01h)
          1. Table 5. TORQUE Register
        3. 7.5.1.3 OFF Register (Address = 0x02h)
          1. Table 6. OFF Register
        4. 7.5.1.4 BLANK Register (Address = 0x03h)
          1. Table 7. BLANK Register
        5. 7.5.1.5 DECAY Register (Address = 0x04h)
          1. Table 8. DECAY Register
        6. 7.5.1.6 Reserved Register Address = 0x05h
          1. Table 9. Reserved Register
        7. 7.5.1.7 DRIVE Register Address = 0x06h
          1. Table 10. DRIVE Register
        8. 7.5.1.8 STATUS Register (Address = 0x07h)
          1. Table 11. STATUS Register
  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 External FET Selection
        2. 8.2.2.2 IDRIVE Configuration
        3. 8.2.2.3 Current Chopping Configuration
        4. 8.2.2.4 Decay Modes
        5. 8.2.2.5 Sense Resistor
      3. 8.2.3 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 Community Resources
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

7.3.8 External FET Selection

In a typical setup, the DRV8704 can support external FETs over 50 nC each. However, this capacity can be lower or higher based on the device operation. For an accurate calculation of FET driving capacity, use Equation 4.

Equation 4. DRV8704 eq_02_Q_lvsd29.gif

Example:

If a DTIME is set to 0 (410 ns), TBLANK is set to 0 (1 µs), and TOFF is set to 0 (525 ns), then the DRV8704 will support Q < 11.5 nC FETs. (Please note that this is an absolute worst-case scenario with a PWM frequency about 430 kHz)

If a DTIME is set to 0 (410 ns), TBLANK is set to 0 (1 µs), and TOFF is set to 0x14 (10 µs), then the DRV8704 will support Q < 59 nC FETs (PWM frequency about 85 kHz).

If a DTIME is set to 0 (410 ns), TBLANK is set to 0 (1 µs), and TOFF is set to 0x60 (48 µs), then the DRV8704 will support Q < 249 nC FETs (PWM frequency about 20 kHz).