SNOSD91B March   2019  – February 2020

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Block Diagram
      2.      Switching Performance
  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 Switching Characteristics
    7. 6.7 Typical Characteristics
  7. 7 Parameter Measurement Information
    1. 7.1 Switching Parameters
    2. 7.2 Turn-on Delays
    3. 7.3 Turn-off Delays
    4. 7.4 Drain Slew Rate
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Direct-Drive GaN Architecture
      2. 8.3.2 Internal Buck-Boost DC-DC Converter
      3. 8.3.3 Internal Auxiliary LDO
      4. 8.3.4 Start Up Sequence
      5. 8.3.5 R-C Decoupling for IN pin
      6. 8.3.6 Low Power Mode
      7. 8.3.7 Fault Detection
        1. 8.3.7.1 Overcurrent Protection
        2. 8.3.7.2 Over-Temperature Protection and UVLO
      8. 8.3.8 Drive Strength Adjustment
    4. 8.4 Safe Operation Area (SOA)
      1. 8.4.1 Repetitive SOA
  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
        1. 9.2.2.1 Slew Rate Selection
          1. 9.2.2.1.1 Startup and Slew Rate with Bootstrap High-Side Supply
        2. 9.2.2.2 Signal Level-Shifting
        3. 9.2.2.3 Buck-Boost Converter Design
    3. 9.3 Dos and Don'ts
  10. 10Power Supply Recommendations
    1. 10.1 Using an Isolated Power Supply
    2. 10.2 Using a Bootstrap Diode
      1. 10.2.1 Diode Selection
      2. 10.2.2 Managing the Bootstrap Voltage
      3. 10.2.3 Reliable Bootstrap Start-up
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Power Loop Inductance
      2. 11.1.2 Signal Ground Connection
      3. 11.1.3 Bypass Capacitors
      4. 11.1.4 Switch-Node Capacitance
      5. 11.1.5 Signal Integrity
      6. 11.1.6 High-Voltage Spacing
      7. 11.1.7 Thermal Recommendations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

10.1 Using an Isolated Power Supply

Using an isolated power supply to power the high-side device has the advantage that it will work regardless of continued GaN device switching or duty cycle. It can also power the high-side device before device switching begins, eliminating the power-loss concern of switching with an unpowered LMG341xR150 (see Startup and Slew Rate with Bootstrap High-Side Supply for details). Finally, a properly-selected isolated supply will contribute fewer parasitics to the switching GaN device, increasing design efficiency. However, the isolated power supply solution is larger and more expensive than the bootstrap solution.

The isolated supply can be constructed from an output of a flyback or FlyBuck™ converter, or using an isolated power module. When using an unregulated supply, ensure that the input to the LMG341xR150 does not exceed the maximum supply voltage. If necessary, a 18 V zener to clamp the VDD voltage supplied by the isolated power converter. Minimizing the inter-winding capacitance of the isolated power supply or transformer is necessary to reduce switching loss in hard-switched applications.