SNVSB38D September   2019  – January 2021 UCC12050

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications and Uses
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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  Power Ratings
    6. 6.6  Insulation Specifications
    7. 6.7  Safety-Related Certifications
    8. 6.8  Safety Limiting Values
    9. 6.9  Electrical Characteristics
    10. 6.10 Switching Characteristics
    11. 6.11 Insulation Characteristics Curves
    12. 6.12 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable and Disable
      2. 7.3.2 UVLO, Power-Up, and Power-Down Behavior
      3. 7.3.3 VISO Load Recommended Operating Area
      4. 7.3.4 Thermal Shutdown
      5. 7.3.5 External Clocking and Synchronization
      6. 7.3.6 VISO Output Voltage Selection
      7. 7.3.7 Electromagnetic Compatibility (EMC) Considerations
    4. 7.4 Device Functional Modes
  8. 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 VISO Output Capacitor Selection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical and Packaging Information

7.3.5 External Clocking and Synchronization

The UCC12050 has an internal oscillator trimmed to drive the transformer at 8.0 MHz. An external clock may be applied at the SYNC pin to override the internal oscillator. This external clock will be divided by 2, so the target range for the external clock signal at SYNC is 16 MHz ±10%. When a valid external clock signal is detected, the internal spread spectrum modulation (SSM) algorithm is disabled. This allows an external clock signal with a unique SSM to be applied. The depth and frequency of SSM is a tradeoff verses low frequency modulated VISO voltage ripple. The SYNC_OK pin is asserted LOW if there is no external SYNC clock or one that is outside of the operating range of the device is detected. In this state, the external clock is ignored and the DC/DC converter is clocked by the internal oscillator. The pin is in high impedance if a valid clock is applied on SYNC.