SLUSDB2B August   2018  – October 2024 UCC28950 , UCC28951

PRODUCTION DATA  

  1.   1
  2. Features
  3. Applications
  4. Description
  5. Pin Configuration and Functions
  6. 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 Timing Requirements
    7. 5.7 Dissipation Ratings
    8. 5.8 Typical Characteristics
  7. Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Start-Up Protection Logic
      2. 6.3.2  Voltage Reference (VREF)
      3. 6.3.3  Error Amplifier (EA+, EA–, COMP)
      4. 6.3.4  Soft-Start and Enable (SS/EN)
      5. 6.3.5  Light-Load Power Saving Features
      6. 6.3.6  Adaptive Delay, (Delay Between OUTA and OUTB, OUTC and OUTD (DELAB, DELCD, ADEL))
      7. 6.3.7  Adaptive Delay (Delay Between OUTA and OUTF, OUTB and OUTE (DELEF, ADELEF)
      8. 6.3.8  Minimum Pulse (TMIN)
      9. 6.3.9  Burst Mode
      10. 6.3.10 Switching Frequency Setting
      11. 6.3.11 Slope Compensation (RSUM)
      12. 6.3.12 Dynamic SR ON/OFF Control (DCM Mode)
      13. 6.3.13 Current Sensing (CS)
      14. 6.3.14 Cycle-by-Cycle Current Limit Current Protection and Hiccup Mode
      15. 6.3.15 Synchronization (SYNC)
      16. 6.3.16 Outputs (OUTA, OUTB, OUTC, OUTD, OUTE, OUTF)
      17. 6.3.17 Supply Voltage (VDD)
      18. 6.3.18 Ground (GND)
    4. 6.4 Device Functional Modes
  8. Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1  Power Loss Budget
        2. 7.2.2.2  Preliminary Transformer Calculations (T1)
        3. 7.2.2.3  QA, QB, QC, QD FET Selection
        4. 7.2.2.4  Selecting LS
        5. 7.2.2.5  Selecting Diodes DB and DC
        6. 7.2.2.6  Output Inductor Selection (LOUT)
        7. 7.2.2.7  Output Capacitance (COUT)
        8. 7.2.2.8  Select FETs QE and QF
        9. 7.2.2.9  Input Capacitance (CIN)
        10. 7.2.2.10 Current Sense Network (CT, RCS, R7, DA)
          1. 7.2.2.10.1 Voltage Loop Compensation Recommendation
      3. 7.2.3 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. Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 Receiving Notification of Documentation Updates
    4. 8.4 Community Resources
    5. 8.5 Trademarks
  10. Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Typical Characteristics

UCC28950 UCC28951 UVLO
                        Thresholds vs TemperatureFigure 5-3 UVLO Thresholds vs Temperature
UCC28950 UCC28951 Supply Current vs TemperatureFigure 5-5 Supply Current vs Temperature
UCC28950 UCC28951 Voltage Reference (VDD = 12V) vs TemperatureFigure 5-7 Voltage Reference (VDD = 12V) vs Temperature
UCC28950 UCC28951 Short-Circuit Current vs TemperatureFigure 5-9 Short-Circuit Current vs Temperature
UCC28950 UCC28951 Nominal Switching Frequency vs TemperatureFigure 5-11 Nominal Switching Frequency vs Temperature
UCC28950 UCC28951 Error
                        Amplifier Offset Voltage vs TemperatureFigure 5-13 Error Amplifier Offset Voltage vs Temperature
UCC28950 UCC28951 ISS Charge Current vs TemperatureFigure 5-15 ISS Charge Current vs Temperature
UCC28950 UCC28951 SS
                        Pullup Threshold vs TemperatureFigure 5-17 SS Pullup Threshold vs Temperature
UCC28950 UCC28951 Current Sense Cycle-by-Cycle Limit vs TemperatureFigure 5-19 Current Sense Cycle-by-Cycle Limit vs Temperature
UCC28950 UCC28951 Outputs Sink Resistance vs TemperatureFigure 5-21 Outputs Sink Resistance vs Temperature
UCC28950 UCC28951 Outputs Source Resistance vs TemperatureFigure 5-23 Outputs Source Resistance vs Temperature
UCC28950 UCC28951 Dead
                        Time Delay vs TemperatureFigure 5-25 Dead Time Delay vs Temperature
UCC28950 UCC28951 DCM
                        Threshold vs TemperatureFigure 5-27 DCM Threshold vs Temperature
UCC28950 UCC28951 UVLO
                        Hysteresis vs TemperatureFigure 5-4 UVLO Hysteresis vs Temperature
UCC28950 UCC28951 Start-Up Current vs TemperatureFigure 5-6 Start-Up Current vs Temperature
UCC28950 UCC28951 Line
                        Voltage Regulation (ILOAD = 10mA) vs TemperatureFigure 5-8 Line Voltage Regulation (ILOAD = 10mA) vs Temperature
UCC28950 UCC28951 Maximum Duty Cycle vs TemperatureFigure 5-10 Maximum Duty Cycle vs Temperature
UCC28950 UCC28951 Maximum Switching Frequency vs TemperatureFigure 5-12 Maximum Switching Frequency vs Temperature
UCC28950 UCC28951 Voltage Error Amplifier (Open-Loop Gain) vs TemperatureFigure 5-14 Voltage Error Amplifier (Open-Loop Gain) vs Temperature
UCC28950 UCC28951 Shutdown, Restart, and Reset Threshold vs TemperatureFigure 5-16 Shutdown, Restart, and Reset Threshold vs Temperature
UCC28950 UCC28951 SS
                        Clamp Voltage vs TemperatureFigure 5-18 SS Clamp Voltage vs Temperature
UCC28950 UCC28951 Current Sense Propagation Delay vs TemperatureFigure 5-20 Current Sense Propagation Delay vs Temperature
UCC28950 UCC28951 Outputs Sink Resistance vs TemperatureFigure 5-22 Outputs Sink Resistance vs Temperature
UCC28950 UCC28951 Outputs Source Resistance vs TemperatureFigure 5-24 Outputs Source Resistance vs Temperature
UCC28950 UCC28951 Dead
                        Time Delay vs TemperatureFigure 5-26 Dead Time Delay vs Temperature