SGLS183C August   2003  – July 2025 UCC2808A-1Q1 , UCC2808A-2Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configurations and Functions
  7. 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 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Pin Descriptions
        1. 7.3.1.1 COMP Pin
        2. 7.3.1.2 OUTA and OUTB Pins
        3. 7.3.1.3 RC Pin
        4. 7.3.1.4 VDD Pin
    4. 7.4 Device Functional Modes
      1. 7.4.1 VCC
      2. 7.4.2 Push-Pull or Half-Bridge Function
  9. 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
      3. 8.2.3 Application Curves
    3. 8.3 Power Supply Recommendations
    4. 8.4 Layout
      1. 8.4.1 Layout Guidelines
      2. 8.4.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Support Resources
    3. 9.3 Trademarks
    4. 9.4 Electrostatic Discharge Caution
    5. 9.5 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • D|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2 Typical Application

A 200kHz push-pull application circuit with a full-wave rectifier is shown in Figure 8-1. The output, VO, provides 5V at 50W maximum and is electrically isolated from the input. Since the UCC2808A-xQ1 is a peak-current-mode controller, the 2N2907 emitter following amplifier (buffers the CT waveform) provides slope compensation, which is necessary for duty ratios greater than 50%. Capacitor decoupling is important with a single ground IC controller, and 1μF is suggested because 1μF is as close to the IC as possible. The controller supply is a series RC for start-up, paralleled with a bias winding on the output inductor used in steady state operation.

Isolation is provided by an optocoupler with regulation completed on the secondary side using the TL431 adjustable precision shunt regulator. Small signal compensation with tight voltage regulation is achieved using TL431 on the secondary side. Many choices exist for the output inductor depending on cost, volume, and mechanical strength. Several design options are iron powder, molypermalloy (MPP), or a ferrite core with an air gap. The main power transformer has a Magnetics® Inc. ER28 size core made of P material for efficient operation at this frequency and temperature. The input voltage ranges from 36V DC to 72V DC.

UCC2808A-1Q1 UCC2808A-2Q1 Typical Application Diagram: 48V In, 5V, 50W Output Figure 8-1 Typical Application Diagram: 48V In, 5V, 50W Output