SNOSD37B march   2017  – april 2023 LMG1205

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 Input and Output
      2. 7.3.2 Start-up and UVLO
      3. 7.3.3 HS Negative Voltage and Bootstrap Supply Voltage Clamping
      4. 7.3.4 Level Shift
    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 VDD Bypass Capacitor
        2. 8.2.2.2 Bootstrap Capacitor
        3. 8.2.2.3 Power Dissipation
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
      1.      Mechanical, Packaging, and Orderable Information

8.2.2.2 Bootstrap Capacitor

The bootstrap capacitor provides the gate charge for the high-side switch, DC bias power for HB undervoltage lockout circuit, and the reverse recovery charge of the bootstrap diode. The required bypass capacitance can be calculated with Equation 2.

Equation 2. CBST>QgH +  IHB + IGSS  × TON + Qrr ∆V

where

  • IHB is the quiescent current of the high-side driver
  • Ton is the maximum on-time period of the high-side transistor
  • IGSS is the gate leakage current of the high-side transistor

A good-quality ceramic capacitor must be used for the bootstrap capacitor. TI recommends placing the bootstrap capacitor as close as possible to the HB and HS pins.