JAJSG76C September   2018  – April 2024 LM5164

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  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  Control Architecture
      2. 6.3.2  Internal VCC Regulator and Bootstrap Capacitor
      3. 6.3.3  Regulation Comparator
      4. 6.3.4  Internal Soft Start
      5. 6.3.5  On-Time Generator
      6. 6.3.6  Current Limit
      7. 6.3.7  N-Channel Buck Switch and Driver
      8. 6.3.8  Synchronous Rectifier
      9. 6.3.9  Enable/Undervoltage Lockout (EN/UVLO)
      10. 6.3.10 Power Good (PGOOD)
      11. 6.3.11 Thermal Protection
    4. 6.4 Device Functional Modes
      1. 6.4.1 Shutdown Mode
      2. 6.4.2 Active Mode
      3. 6.4.3 Sleep 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 Switching Frequency (RRON)
        3. 7.2.2.3 Buck Inductor (LO)
        4. 7.2.2.4 Output Capacitor (COUT)
        5. 7.2.2.5 Input Capacitor (CIN)
        6. 7.2.2.6 Type-3 Ripple Network
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
        1. 7.4.1.1 Compact PCB Layout for EMI Reduction
        2. 7.4.1.2 Feedback Resistors
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 サード・パーティ製品に関する免責事項
      2. 8.1.2 Development Support
        1. 8.1.2.1 Custom Design With WEBENCH® Tools
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 ドキュメントの更新通知を受け取る方法
    4. 8.4 サポート・リソース
    5. 8.5 Trademarks
    6. 8.6 静電気放電に関する注意事項
    7. 8.7 用語集
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.7 N-Channel Buck Switch and Driver

The LM5164 integrates an N-channel buck switch and associated floating high-side gate driver. The gate-driver circuit works in conjunction with an external bootstrap capacitor and an internal high-voltage bootstrap diode. A high-quality 2.2-nF, 50-V X7R ceramic capacitor connected between the BST and SW pins provides the voltage to the high-side driver during the buck switch on-time. See the Section 6.3.2 section for limitations. During the off-time, the SW pin is pulled down to approximately 0 V, and the bootstrap capacitor charges from the internal VCC through the internal bootstrap diode. The minimum off-timer, set to 50 ns (typical), ensures a minimum time each cycle to recharge the bootstrap capacitor. When the on-time is less than 300 ns, the minimum off-timer is forced to 250 ns to ensure that the BST capacitor is charged in a single cycle. This is vital during wake up from sleep mode when the BST capacitor is most likely discharged.