SLUSBF3D July   2013  – March 2018 UCC28740

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Application Diagram
      2.      Typical V-I Diagram
  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 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Detailed Pin Description
      2. 7.3.2 Valley-Switching and Valley-Skipping
      3. 7.3.3 Startup Operation
      4. 7.3.4 Fault Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Secondary-Side Optically Coupled Constant-Voltage (CV) Regulation
      2. 7.4.2 Primary-Side Constant-Current (CC) Regulation
  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 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Standby Power Estimate and No-Load Switching Frequency
        3. 8.2.2.3 Input Bulk Capacitance and Minimum Bulk Voltage
        4. 8.2.2.4 Transformer Turns-Ratio, Inductance, Primary Peak Current
        5. 8.2.2.5 Transformer Parameter Verification
        6. 8.2.2.6 VS Resistor Divider, Line Compensation
        7. 8.2.2.7 Output Capacitance
        8. 8.2.2.8 VDD Capacitance, CVDD
        9. 8.2.2.9 Feedback Network Biasing
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 VDD Pin
      2. 10.1.2 VS Pin
      3. 10.1.3 FB Pin
      4. 10.1.4 GND Pin
      5. 10.1.5 CS Pin
      6. 10.1.6 DRV Pin
      7. 10.1.7 HV Pin
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design With WEBENCH® Tools
      2. 11.1.2 Device Nomenclature
        1. 11.1.2.1  Capacitance Terms in Farads
        2. 11.1.2.2  Duty Cycle Terms
        3. 11.1.2.3  Frequency Terms in Hertz
        4. 11.1.2.4  Current Terms in Amperes
        5. 11.1.2.5  Current and Voltage Scaling Terms
        6. 11.1.2.6  Transformer Terms
        7. 11.1.2.7  Power Terms in Watts
        8. 11.1.2.8  Resistance Terms in Ohms
        9. 11.1.2.9  Timing Terms in Seconds
        10. 11.1.2.10 Voltage Terms in Volts
        11. 11.1.2.11 AC Voltage Terms in VRMS
        12. 11.1.2.12 Efficiency Terms
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10.1.5 CS Pin

A small filter capacitor may be placed on CS to GND, with short traces, to filter any ringing that may be present at light load conditions when driving MOSFETs with large gate capacitance. This capacitor may not be required in all designs; however, it is wise to put a place holder for it in your designs. The current sense resistor should be returned to the ground terminal of the input bulk capacitor to minimize the loop area containing the input capacitor, the transformer, the MOSFET, and the current sense resistor.