SNOSDL1 December   2024 LMG3650R035

ADVANCE INFORMATION  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Device Comparison
  6. Pin Configuration and Functions
  7. 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
  8. Parameter Measurement Information
    1. 7.1 Switching Parameters
      1. 7.1.1 Turn-On Times
      2. 7.1.2 Turn-Off Times
      3. 7.1.3 Drain-Source Turn-On and Turn-off Slew Rate
      4. 7.1.4 Zero-Voltage Detection Times (LMG3656R035 only)
  9. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
      1. 8.2.1 LMG3650R035 Functional Block Diagram
      2. 8.2.2 LMG3651R035 Functional Block Diagram
      3. 8.2.3 LMG3656R035 Functional Block Diagram
      4. 8.2.4 LMG3657R035 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Drive Strength Adjustment
      2. 8.3.2 VDD Supply
      3. 8.3.3 Overcurrent and Short-Circuit Protection
      4. 8.3.4 Overtemperature Protection
      5. 8.3.5 UVLO Protection
      6. 8.3.6 Fault Reporting
      7. 8.3.7 Auxiliary LDO (LMG3651R035 Only)
      8. 8.3.8 Zero-Voltage Detection (ZVD) (LMG3656R035 Only)
      9. 8.3.9 Zero-Current Detection (ZCD) (LMG3657R035 Only)
    4. 8.4 Device Functional Modes
  10. 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
        2. 9.2.2.2 Signal Level-Shifting
    3. 9.3 Power Supply Recommendations
      1. 9.3.1 Using an Isolated Power Supply
      2. 9.3.2 Using a Bootstrap Diode
        1. 9.3.2.1 Diode Selection
        2. 9.3.2.2 Managing the Bootstrap Voltage
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
  11. 10Device and Documentation Support
    1. 10.1 Receiving Notification of Documentation Updates
    2. 10.2 Support Resources
    3. 10.3 Trademarks
    4. 10.4 Electrostatic Discharge Caution
    5. 10.5 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

Package Options

Mechanical Data (Package|Pins)
  • KLA|9
Thermal pad, mechanical data (Package|Pins)
Orderable Information

Signal Level-Shifting

In half-bridges, high-voltage level shifters or digital isolators must be used to provide isolation for signal paths between the high-side device and control circuit. Using an isolator is optional for the low-side device. However, using and isolator equalizes the propagation delays between the high-side and low-side signal paths, and provides the ability to use different grounds for the GaN device and the controller. If an isolator is not used on the low-side device, the control ground and the power ground must be connected at the device and nowhere else on the board. For more information, see Layout Guidelines. With fast-switching devices, common ground inductance can easily cause noise issues without the use of an isolator.

Choosing a digital isolator for level-shifting is important for improvement of noise immunity. As GaN device can easily create high dv/dt, > 50V/ns, in hard-switching applications, TI highly recommends to use isolators with high common-mode transient immunity (CMTI) and low barrier capacitance. Isolators with low CMTI can easily generate false signals, which could cause shoot-through. The barrier capacitance is part of the isolation capacitance between the signal ground and power ground, which is in direct proportion to the common mode current and EMI emission generated during the switching. Additionally, TI strongly encourages to select isolators which are not edge-triggered. In an edge-triggered isolator, a high dv/dt event can cause the isolator to flip states and cause circuit malfunction.

Generally, ON/OFF keyed isolators with default output low are preferred. Default low state ensures the system will not shoot-through when starting up or recovering from fault events. As a high CMTI event would only cause a very short (a few nanoseconds) false pulse, TI recommends a low pass filter, like 300Ω and 22pF R-C filter, to be placed at the driver input to filter out these false pulses.