SLUSDU4A December   2020  – May 2022 UCC27289

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 Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Enable
      2. 7.3.2 Start-up and UVLO
      3. 7.3.3 Input Stages
      4. 7.3.4 Level Shifter
      5. 7.3.5 Output Stage
      6. 7.3.6 Negative Voltage Transients
    4. 7.4 Device Functional Modes
  8. 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
        1. 8.2.2.1 Select Bootstrap and VDD Capacitor
        2. 8.2.2.2 External Bootstrap Diode and Series Resistor
        3. 8.2.2.3 Estimate Driver Power Losses
        4. 8.2.2.4 Selecting External Gate Resistor
        5. 8.2.2.5 Delays and Pulse Width
        6. 8.2.2.6 VDD and Input Filter
        7. 8.2.2.7 Transient Protection
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    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

8.2.2.2 External Bootstrap Diode and Series Resistor

The UCC27289 has integrated bootstrap diode, necessary to generate the high-side bias for HO to work satisfactorily. The characteristics of this diode are important to achieve efficient, reliable operation. If external bootstrap diode is needed then the diode characteristics to consider are reverse voltage handling capability, repetitive peak forward current, forward voltage drop, forward and reverse recovery time, and dynamic resistance. As the UCC27289 is 100V rated gate driver, the external bootstrap diode must be at least 100V rated. Peak forward current rating depends on multiple system parameters such as high-side and low-side duty cycle, value of bootstrap capacitor, and allowed voltage ripple on the bootstrap capacitor. Generally, low forward voltage drop diodes are preferred for low power loss during charging of the bootstrap capacitor. Schottky diodes have low forward voltage drop and can be used with the UCC27289. The dynamic characteristics to consider are diode recovery time and stored charge. Diode that has less than 50ns of forward and reverse recovery times is suitable in most applications.

Specifically in very high switching frequency applications, for example in excess of 1 MHz, and where the low-side minimum pulse widths are very small, the diode peak forward current could be very high and peak reverse current could also be very high, specifically if high bootstrap capacitor value has been chosen. In such applications it might be advisable to use Schottkey diode as bootstrap diode. MURS210 diode will work with the application example described here.