SLUS224H September   1994  – October 2024 UC1842A , UC1843A , UC1844A , UC1845A , UC2842A , UC2843A , UC2844A , UC2845A , UC3842A , UC3842M , UC3843A , UC3844A , UC3845A

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 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Pulse-by-Pulse Current Limiting
      2. 6.3.2 Current Sense Circuit
      3. 6.3.3 Error Amplifier Configuration
      4. 6.3.4 Undervoltage Lockout
      5. 6.3.5 Oscillator
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Undervoltage Lockout (UVLO) Start-Up
      3. 6.4.3 UVLO Turnoff Mode
  8. 7 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 Custom Design With WEBENCH® Tools
        2. 7.2.2.2 UC2842A Design Procedure
      3. 7.2.3 Application Curves
  9. 8 Power Supply Recommendations
  10. 9 Layout
    1. 9.1 Layout Guidelines
    2. 9.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 Custom Design With WEBENCH® Tools
      2. 10.1.2 Device Nomenclature
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Related Links
    4. 10.4 Receiving Notification of Documentation Updates
    5. 10.5 Support Resources
    6. 10.6 Trademarks
    7. 10.7 Electrostatic Discharge Caution
    8. 10.8 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

6.1 Overview

The UCx84xA family of fixed-frequency pulse-width-modulator (PWM) controllers are designed to operate at switching frequencies of 500 kHz. These controllers are designed for peak current mode (PCM) and can be used in isolated and non-isolated power supply designs. These controllers can drive FETs directly from the output, which is capable of sourcing and sinking up to 1 A of gate driver current. These devices also have a built-in low-impedance amplifier that can be used in non-isolated designs to control the power supply output voltage and feedback loop.