SLUSFX8 September   2026 UCC218302-Q1

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 Power Ratings
    6. 5.6 Insulation Specifications
    7. 5.7 Electrical Characteristics
    8. 5.8 Switching Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Power Supply
      2. 6.3.2  VCC Undervoltage Lockout (UVLO)
      3. 6.3.3  Input Filters for IN+, IN-, and RST/EN
      4. 6.3.4  Active Pulldown
      5. 6.3.5  Short Circuit Clamping
      6. 6.3.6  Internal Active Miller Clamp
      7. 6.3.7  Desaturation (DESAT) Protection
      8. 6.3.8  Soft Shutdown (SSD)
      9. 6.3.9  Fault (FLT), Reset, and Enable (RST/EN)
      10. 6.3.10 Output Gate Voltage Monitor
      11. 6.3.11 Active Short Circuit (ASC) Support
      12. 6.3.12 Overtemperature Protection
    4. 6.4 Device Functional Modes
  8. 7 Applications and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Application Schematic
      2. 7.2.2 Design Requirements
      3. 7.2.3 Detailed Design Procedure
        1. 7.2.3.1 Input Filters for IN+, IN-, and RST/EN
        2. 7.2.3.2 FLT, RDY, and RST/EN Pin Circuitry
        3. 7.2.3.3 Gate Driver Output Resistors
        4. 7.2.3.4 Overcurrent and Short Circuit Protection With DESAT
      4. 7.2.4 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Third-Party Products Disclaimer
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Support Resources
    5. 8.5 Trademarks
    6. 8.6 Electrostatic Discharge Caution
    7. 8.7 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
    1. 10.1 Mechanical Data

6.3.8 Soft Shutdown (SSD)

When detecting a DESAT fault, the UCC218302-Q1 initiates a soft shutdown (SSD) to protect the power semiconductor device. When an overcurrent or short circuit event occurs, the SSD feature slowly discharges the gate voltage to limit the overshoot voltage on the switching device created by high dI/dt due to the channel current. A tradeoff occurs between the overshoot voltage and the short-circuit energy. The turn-off speed must be slow enough to limit the overshoot voltage, but the shutdown time must not be too long that the large energy dissipation in the device can cause breakdown. The UCC218302-Q1 provides an internal pulldown FET that can be used with an external resistor to optimize the discharge current of the gate. When a DESAT fault is detected, OUTHx and OUTLx are Hi-Z so that the gate is not driven by the main driver outputs. The internal pulldown MOSFET on the SSD pin turns on for tSSD to let the gate discharge. After this time, CLMPI and OUTLx are driven low to hold the power semiconductor device off. Figure 6-11 shows a simplified block diagram and Figure 6-10 shows a timing diagrams.

UCC218302-Q1 Soft Shutdown Figure 6-11 Soft Shutdown