SLUSC05D July   2014  – May 2016 UCC28880

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 CharacteristicsTypical Characteristics graphs 1 through 7.
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
    4. 7.4 Device Functional Modes
      1. 7.4.1 Startup Operation
      2. 7.4.2 Feedback and Voltage Control Loop
      3. 7.4.3 PWM Controller
      4. 7.4.4 Current Limit
      5. 7.4.5 Inductor Current Runaway Protection
      6. 7.4.6 Thermal Shutdown Over-Temperature Protection section to Thermal Shutdown section.
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 12-V, 100-mA Low-Side Buck Converter
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Custom Design with WEBENCH Tools
          2. 8.2.1.2.2 Input Stage (RF, D2, D3, C1, C2, L2)
          3. 8.2.1.2.3 Regulator Capacitor (CVDD)
          4. 8.2.1.2.4 Freewheeling Diode (D1)Freewheeling Diode (D1) section.
          5. 8.2.1.2.5 Output Capacitor (CL)
          6. 8.2.1.2.6 Load Resistor (RL)
          7. 8.2.1.2.7 Inductor (L1)
          8. 8.2.1.2.8 Feedback Path (Q1, RFB1, RFB2)
        3. 8.2.1.3 Application Curves
      2. 8.2.2 12-V, 100-mA, High-Side Buck Converter
        1. 8.2.2.1 Design Requirements
        2. 8.2.2.2 Detailed Design Procedure
          1. 8.2.2.2.1 Introduction
          2. 8.2.2.2.2 Feedback Path (CFB, RFB1 and RFB2) and Load Resistor (RL)
        3. 8.2.2.3 Application Curves
      3. 8.2.3 Additional UCC28880 Application Topologies
        1. 8.2.3.1 Low-Side Buck and LED Driver - Direct Feedback (Level Shifted)
        2. 8.2.3.2 12-V, 100-mA High-Side Buck Converter
        3. 8.2.3.3 Non-Isolated, Low-Side Buck-Boost Converter
        4. 8.2.3.4 Non-Isolated, High-Side Buck-Boost Converter
        5. 8.2.3.5 Non-Isolated Flyback Converter
        6. 8.2.3.6 Isolated Flyback Converter
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines Layout Guidelines section.
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Custom Design with WEBENCH Tools
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

10 Layout

10.1 Layout Guidelines

  • In both buck and buck-boost low-side configurations, the copper area of the switching node DRAIN should be minimized to reduce EMI.
  • Similarly, the copper area of the FB pin should be minimized to reduce coupling to feedback path. Loop CL, Q1, RFB1 should be minimized to reduce coupling to feedback path.
  • In high-side buck and buck boost the GND, VDD and FB pins are all part of the switching node so the copper area connected with these pins should be optimized. Large copper area allows better thermal management, but it causes more common mode EMI noise. Use the minimum copper area that is required to handle the thermal dissipation.
  • Minimum distance between 700-V coated traces is 1.41 mm (60 mils).

10.2 Layout Example

Figure 29 shows and example PCB layout for UCC28880 in low-side buck configuration.

UCC28880 layoutexample2_lusc05.gif Figure 29. UCC28880 Layout Example