SNOSDA8C October   2020  – February 2024 LMG3422R050 , LMG3426R050

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Switching Characteristics
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
    1. 6.1 Switching Parameters
      1. 6.1.1 Turn-On Times
      2. 6.1.2 Turn-Off Times
      3. 6.1.3 Drain-Source Turn-On Slew Rate
      4. 6.1.4 Turn-On and Turn-Off Switching Energy
      5. 6.1.5 Zero-Voltage Detection Times
    2. 6.2 Safe Operation Area (SOA)
      1. 6.2.1 Repetitive SOA
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
      1. 7.2.1 LMG3422R050 Functional Block Diagram
      2. 7.2.2 LMG3426R050 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  GaN FET Operation Definitions
      2. 7.3.2  Direct-Drive GaN Architecture
      3. 7.3.3  Drain-Source Voltage Capability
      4. 7.3.4  Internal Buck-Boost DC-DC Converter
      5. 7.3.5  VDD Bias Supply
      6. 7.3.6  Auxiliary LDO
      7. 7.3.7  Fault Protection
        1. 7.3.7.1 Overcurrent Protection and Short-Circuit Protection
        2. 7.3.7.2 Overtemperature Shutdown Protection
        3. 7.3.7.3 UVLO Protection
        4. 7.3.7.4 High-Impedance RDRV Pin Protection
        5. 7.3.7.5 Fault Reporting
      8. 7.3.8  Drive-Strength Adjustment
      9. 7.3.9  Temperature-Sensing Output
      10. 7.3.10 Ideal-Diode Mode Operation
        1. 7.3.10.1 Overtemperature-Shutdown Ideal-Diode Mode
      11. 7.3.11 Zero-Voltage Detection (ZVD)
    4. 7.4 Start-Up Sequence
    5. 7.5 Device Functional Modes
  9. 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 Slew Rate Selection
        2. 8.2.2.2 Signal Level-Shifting
        3. 8.2.2.3 Buck-Boost Converter Design
      3. 8.2.3 Application Curves
    3. 8.3 Do's and Don'ts
    4. 8.4 Power Supply Recommendations
      1. 8.4.1 Using an Isolated Power Supply
      2. 8.4.2 Using a Bootstrap Diode
        1. 8.4.2.1 Diode Selection
        2. 8.4.2.2 Managing the Bootstrap Voltage
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Solder-Joint Reliability
        2. 8.5.1.2 Power-Loop Inductance
        3. 8.5.1.3 Signal-Ground Connection
        4. 8.5.1.4 Bypass Capacitors
        5. 8.5.1.5 Switch-Node Capacitance
        6. 8.5.1.6 Signal Integrity
        7. 8.5.1.7 High-Voltage Spacing
        8. 8.5.1.8 Thermal Recommendations
      2. 8.5.2 Layout Examples
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Export Control Notice
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
  • RQZ|54
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.3.10 Ideal-Diode Mode Operation

Off-state FETs act like diodes by blocking current in one direction (first quadrant) and allowing current in the other direction (third quadrant) with a corresponding diode like voltage drop. FETs, though, can also conduct third-quadrant current in the on-state at a significantly lower voltage drop. Ideal-diode mode (IDM) is when an FET is controlled to block first-quadrant current by going to the off-state and conduct third-quadrant current by going to the on-state, thus achieving an ideal lower voltage drop.

FET off-state third-quadrant current flow is commonly seen in power converters, both in normal and fault situations. As explained in GaN FET Operation Definitions, GaN FETs do not have an intrinsic p-n junction body diode to conduct off-state third-quadrant current. Instead, the off-state third-quadrant voltage drop for the LMG342xR050 is several times higher than a p-n junction voltage drop, which can impact efficiency in normal operation and device ruggedness in fault conditions.

To improve device ruggedness in a GaN FET overtemperature fault situation, LMG342xR050 devices implement a GaN FET overtemperature-shutdown ideal-diode mode (OTSD-IDM) function as referenced in Overtemperature Shutdown Protection. The OTSD-IDM feature is described in more detail in the following section.