SLUS270G March   1999  – May 2020 UCC2800 , UCC2801 , UCC2802 , UCC2803 , UCC2804 , UCC2805

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Device Comparison Table
  7. 7 Pin Configuration and Functions
    1.     Pin Functions
  8. 8 Specifications
    1. 8.1 Absolute Maximum Ratings
    2. 8.2 ESD Ratings
    3. 8.3 Recommended Operating Conditions
    4. 8.4 Thermal Information
    5. 8.5 Electrical Characteristics
    6. 8.6 Typical Characteristics
  9. 9 Detailed Description
    1. 9.1 Overview
    2. 9.2 Functional Block Diagram
    3. 9.3 Feature Description
      1. 9.3.1  Detailed Pin Description
        1. 9.3.1.1 COMP
        2. 9.3.1.2 FB
        3. 9.3.1.3 CS
        4. 9.3.1.4 RC
        5. 9.3.1.5 GND
        6. 9.3.1.6 OUT
        7. 9.3.1.7 VCC
        8. 9.3.1.8 Pin 8 (REF)
      2. 9.3.2  Undervoltage Lockout (UVLO)
      3. 9.3.3  Self-Biasing, Active Low Output
      4. 9.3.4  Reference Voltage
      5. 9.3.5  Oscillator
      6. 9.3.6  Synchronization
      7. 9.3.7  PWM Generator
      8. 9.3.8  Minimum Off-Time Setting (Dead-Time Control)
      9. 9.3.9  Leading Edge Blanking
      10. 9.3.10 Minimum Pulse Width
      11. 9.3.11 Current Limiting
      12. 9.3.12 Overcurrent Protection and Full Cycle Restart
      13. 9.3.13 Soft Start
      14. 9.3.14 Slope Compensation
    4. 9.4 Device Functional Modes
      1. 9.4.1 Normal Operation
      2. 9.4.2 UVLO Mode
      3. 9.4.3 Soft Start Mode
      4. 9.4.4 Fault Mode
  10. 10Application and Implementation
    1. 10.1 Application Information
    2. 10.2 Typical Application
      1. 10.2.1 Design Requirements
      2. 10.2.2 Detailed Design Procedure
        1. 10.2.2.1 Current Sensing Network
        2. 10.2.2.2 Gate Drive Resistor
        3. 10.2.2.3 Vref Capacitor
        4. 10.2.2.4 RTCT
        5. 10.2.2.5 Start-Up Circuit
        6. 10.2.2.6 Voltage Feedback Compensation
          1. 10.2.2.6.1 Power Stage Gain, Zeroes, and Poles
          2. 10.2.2.6.2 Compensation Loop
      3. 10.2.3 Application Curves
  11. 11Power Supply Recommendations
  12. 12Layout
    1. 12.1 Layout Guidelines
    2. 12.2 Layout Example
  13. 13Device and Documentation Support
    1. 13.1 Support Resources
    2. 13.2 Trademarks
    3. 13.3 Electrostatic Discharge Caution
    4. 13.4 Glossary
    5. 13.5 Related Links
  14. 14Mechanical, Packaging, and Orderable Information

Package Options

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

9.3.1.1 COMP

Unlike other devices, the error amplifier in the UCC280x family is a true, low output impedance, 2-MHz operational amplifier. As such, the COMP terminal can both source and sink current. However, the error amplifier is internally current-limited, so that one can command zero duty cycle by externally forcing COMP to GND.

The UCC280x has a true low output impedance error amplifier which both sources and sinks current. The error amplifier associated with the UC3842 family is an open collector in parallel with a current source.

The UCC280x has power-up soft start and fault soft start built on-chip with a fixed COMP rise time to 5 V in
4 ms. Therefore, no external soft-start circuitry is required, saving 1 resistor, 1 capacitor, and 1 PNP transistor.