JAJSL67B June   2021  – February 2025 LM25148-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特長
  3. 2 アプリケーション
  4. 3 概要
  5. 4 概要 (続き)
  6. 5 Orderable Part Numbers
  7. 6 Pin Configuration and Functions
    1. 6.1 Wettable Flanks
  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 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  Input Voltage Range (VIN)
      2. 8.3.2  High-Voltage Bias Supply Regulator (VCC, VCCX, VDDA)
      3. 8.3.3  Precision Enable (EN)
      4. 8.3.4  Power-Good Monitor (PG)
      5. 8.3.5  Switching Frequency (RT)
      6. 8.3.6  Dual Random Spread Spectrum (DRSS)
      7. 8.3.7  Soft Start
      8. 8.3.8  Output Voltage Setpoint (FB)
      9. 8.3.9  Minimum Controllable On Time
      10. 8.3.10 Error Amplifier and PWM Comparator (FB, EXTCOMP)
      11. 8.3.11 Slope Compensation
      12. 8.3.12 Inductor Current Sense (ISNS+, VOUT)
        1. 8.3.12.1 Shunt Current Sensing
        2. 8.3.12.2 Inductor DCR Current Sensing
      13. 8.3.13 Hiccup Mode Current Limiting
      14. 8.3.14 High-Side and Low-Side Gate Drivers (HO, LO)
      15. 8.3.15 Output Configurations (CNFG)
      16. 8.3.16 Single-Output Dual-Phase Operation
    4. 8.4 Device Functional Modes
      1. 8.4.1 Sleep Mode
      2. 8.4.2 Pulse Frequency Modulation and Synchronization (PFM/SYNC)
      3. 8.4.3 Thermal Shutdown
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Power Train Components
        1. 9.1.1.1 Buck Inductor
        2. 9.1.1.2 Output Capacitors
        3. 9.1.1.3 Input Capacitors
        4. 9.1.1.4 Power MOSFETs
        5. 9.1.1.5 EMI Filter
      2. 9.1.2 Error Amplifier and Compensation
    2. 9.2 Typical Applications
      1. 9.2.1 Design 1 – High Efficiency 2.1MHz Synchronous Buck Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design with WEBENCH® Tools
          2. 9.2.1.2.2 Buck Inductor
          3. 9.2.1.2.3 Current-Sense Resistance
          4. 9.2.1.2.4 Output Capacitors
          5. 9.2.1.2.5 Input Capacitors
          6. 9.2.1.2.6 Frequency Set Resistor
          7. 9.2.1.2.7 Feedback Resistors
          8. 9.2.1.2.8 Compensation Components
        3. 9.2.1.3 Application Curves
      2. 9.2.2 Design 2 – High Efficiency 440-kHz Synchronous Buck Regulator
        1. 9.2.2.1 Design Requirements
        2. 9.2.2.2 Detailed Design Procedure
        3. 9.2.2.3 Application Curves
      3. 9.2.3 Design 3 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator
        1. 9.2.3.1 Design Requirements
        2. 9.2.3.2 Detailed Design Procedure
        3. 9.2.3.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Power Stage Layout
        2. 9.4.1.2 Gate-Drive Layout
        3. 9.4.1.3 PWM Controller Layout
        4. 9.4.1.4 Thermal Design and Layout
        5. 9.4.1.5 Ground Plane Design
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 Custom Design with WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
        1. 10.2.1.1 PCB Layout Resources
        2. 10.2.1.2 Thermal Design Resources
    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. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

9.2.3 Design 3 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator

Figure 9-28 shows the schematic diagram of a dual-phase synchronous buck regulator with output voltage of 3.3 V and a rated load current of 20 A. In this example, the target half-load and full-load efficiencies are 95% and 92%, respectively, based on a nominal input voltage of 12 V that ranges from 4 V to 36 V. The switching frequency is set at 400 kHz by resistors RRT1 and RRT2.

LM25148-Q1 Application Circuit 3 With Two LM25148-Q1 Buck Regulators Switching at 400 kHz Figure 9-28 Application Circuit 3 With Two LM25148-Q1 Buck Regulators Switching at 400 kHz
Note:

A design with three or more phases is feasible when appropriately added phase-shifted clock signals are available. For example, a 4-phase design requires four LM25148-Q1 controllers with 0°, 90°, 180° and 270° external SYNC signals to achieve the excellent phase separation of 360° divided by the total number of phases.