JAJSNH5B february   2022  – may 2023 LMQ66410 , LMQ66420 , LMQ66430

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 System Characteristics
    7. 7.7 Typical Characteristics
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Enable, Start-Up, and Shutdown
      2. 8.3.2  Adjustable Switching Frequency (with RT)
      3. 8.3.3  Power-Good Output Operation
      4. 8.3.4  Internal LDO, VCC, and VOUT/FB Input
      5. 8.3.5  Bootstrap Voltage and VBOOT-UVLO (BOOT Terminal)
      6. 8.3.6  Output Voltage Selection
      7. 8.3.7  Spread Spectrum
      8. 8.3.8  Soft Start and Recovery from Dropout
        1. 8.3.8.1 Recovery from Dropout
      9. 8.3.9  Current Limit and Short Circuit
      10. 8.3.10 Thermal Shutdown
      11. 8.3.11 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
        1. 8.4.3.1 CCM Mode
        2. 8.4.3.2 Auto Mode – Light Load Operation
          1. 8.4.3.2.1 Diode Emulation
          2. 8.4.3.2.2 Frequency Reduction
        3. 8.4.3.3 FPWM Mode – Light Load Operation
        4. 8.4.3.4 Minimum On-Time (High Input Voltage) Operation
        5. 8.4.3.5 Dropout
  10. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Synchronous Buck Regulator at 400 kHz
      2. 9.2.2 Design Requirements
      3. 9.2.3 Detailed Design Procedure
        1. 9.2.3.1  Choosing the Switching Frequency
        2. 9.2.3.2  Setting the Output Voltage
          1. 9.2.3.2.1 VOUT / FB for Adjustable Output
        3. 9.2.3.3  Inductor Selection
        4. 9.2.3.4  Output Capacitor Selection
        5. 9.2.3.5  Input Capacitor Selection
        6. 9.2.3.6  CBOOT
        7. 9.2.3.7  VCC
        8. 9.2.3.8  CFF Selection
        9. 9.2.3.9  External UVLO
        10. 9.2.3.10 Maximum Ambient Temperature
      4. 9.2.4 Application Curves
    3. 9.3 Best Design Practices
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
        1. 9.5.1.1 Ground and Thermal Considerations
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 サード・パーティ製品に関する免責事項
      2. 10.1.2 Device Nomenclature
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 ドキュメントの更新通知を受け取る方法
    4. 10.4 サポート・リソース
    5. 10.5 Trademarks
    6. 10.6 静電気放電に関する注意事項
    7. 10.7 用語集
  12. 11Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ（パッケージ｜ピン）
サーマルパッド・メカニカル・データ
発注情報

8.4.3.1 CCM Mode

The following operating description of the device refers to Section 8.2 and to the waveforms in Figure 8-13. In CCM, the device supplies a regulated output voltage by turning on the internal high-side (HS) and low-side (LS) switches with varying duty cycle (D). During the HS switch on time, the SW pin voltage, VSW, swings up to approximately VIN, and the inductor current, iL, increases with a linear slope. The HS switch is turned off by the control logic. During the HS switch off time, tOFF, the LS switch is turned on. Inductor current discharges through the LS switch, which forces the VSW to swing below ground by the voltage drop across the LS switch. The converter loop adjusts the duty cycle to maintain a constant output voltage. D is defined by the on time of the HS switch over the switching period:

Equation 3. D = TON / TSW

In an ideal buck converter where losses are ignored, D is proportional to the output voltage and inversely proportional to the input voltage:

Equation 4. D = VOUT / VIN
GUID-20220126-SS0I-MS64-FKS0-S3GPKMHWJJXJ-low.svg Figure 8-13 SW Voltage and Inductor Current Waveforms in Continuous Conduction Mode (CCM)