JAJSL98B October   2020  – June 2021 LMG3522R030-Q1 , LMG3525R030-Q1

ADVANCE INFORMATION  

  1. 1 特長
  2. 2 アプリケーション
  3. 3 概要
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Switching Characteristics
  8. 8 Parameter Measurement Information
    1. 8.1 Switching Parameters
      1. 8.1.1 Turn-On Delays
      2. 8.1.2 Turn-Off Delays
      3. 8.1.3 Drain Slew Rate
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1 Direct-Drive GaN Architecture
      2. 9.3.2 Drain-Source Voltage Capability
      3. 9.3.3 Internal Buck-Boost DC-DC Converter
      4. 9.3.4 VDD Bias Supply
      5. 9.3.5 Auxiliary LDO
      6. 9.3.6 Fault Detection
        1. 9.3.6.1 Overcurrent Protection and Short-Circuit Protection
        2. 9.3.6.2 Overtemperature Shutdown
        3. 9.3.6.3 UVLO Protection
        4. 9.3.6.4 Fault Reporting
      7. 9.3.7 Drive Strength Adjustment
      8. 9.3.8 Temperature-Sensing Output
      9. 9.3.9 Sync-FET Mode Operation
    4. 9.4 Device Functional Modes
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Slew Rate Selection
          1. 10.2.2.1.1 Start-Up and Slew Rate With Bootstrap High-Side Supply
        2. 10.2.2.2 Signal Level-Shifting
        3. 10.2.2.3 Buck-Boost Converter Design
    3. 10.3 Do's and Don'ts
  11. 11Power Supply Recommendations
    1. 11.1 Using an Isolated Power Supply
    2. 11.2 Using a Bootstrap Diode
      1. 11.2.1 Diode Selection
      2. 11.2.2 Managing the Bootstrap Voltage
  12. 12Layout
    1. 12.1 Layout Guidelines
      1. 12.1.1 Power Loop Inductance
      2. 12.1.2 Signal Ground Connection
      3. 12.1.3 Bypass Capacitors
      4. 12.1.4 Switch-Node Capacitance
      5. 12.1.5 Signal Integrity
      6. 12.1.6 High-Voltage Spacing
      7. 12.1.7 Thermal Recommendations
    2. 12.2 Layout Examples
  13. 13Device and Documentation Support
    1. 13.1 Documentation Support
      1. 13.1.1 Related Documentation
    2. 13.2 Receiving Notification of Documentation Updates
    3. 13.3 サポート・リソース
    4. 13.4 Trademarks
    5. 13.5 Electrostatic Discharge Caution
    6. 13.6 Export Control Notice
    7. 13.7 Glossary
  14. 14Mechanical, Packaging, and Orderable Information
    1. 14.1 Tape and Reel Information

パッケージ・オプション

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メカニカル・データ（パッケージ｜ピン）
  • RQS|52
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発注情報

11.2.2 Managing the Bootstrap Voltage

In a synchronous buck or other converter where the low-side switch occasionally operates in third-quadrant, the bootstrap supply charges through a path that includes the third-quadrant voltage drop of the low-side LMG352xR030-Q1 during the dead time as shown in Figure 11-1. This third-quadrant drop can be large, which may over-charge the bootstrap supply in certain conditions. The VDD supply of LMG352xR030-Q1 must be kept below 18 V.

GUID-88971DA8-A73A-46F8-B3CD-7AE1D6D887DD-low.gifFigure 11-1 Charging Path for Bootstrap Diode

As shown in Figure 11-2, the recommended bootstrap supply includes a bootstrap diode, a series resistor, and a 16-V TVS or zener diode in parallel with the VDD bypass capacitor to prevent damaging the high-side LMG352xR030-Q1. The series resistor limits the charging current at start-up. and when the low-side device is operating in third-quadrant mode. This resistor must be selected to allow sufficient current to power the LMG352xR030-Q1 at the desired operating frequency. At 100-kHz operation, a value of approximately 2 Ω is recommended. At higher frequencies, this resistor value should be reduced or the resistor omitted entirely to ensure sufficient supply current.

GUID-961E89E3-2352-46B3-AE7A-186DB506851E-low.gif Figure 11-2 Suggested Bootstrap Regulation Circuit