ZHCSSC1B June   2015  – December 2024 LV14240

PRODUCTION DATA  

  1.   1
  2. 特性
  3. 应用
  4. 说明
  5. Pin Configuration and Functions
  6. 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 Switching Characteristics
    7. 5.7 Typical Characteristics
  7. Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Fixed Frequency Peak Current Mode Control
      2. 6.3.2  Slope Compensation
      3. 6.3.3  Low Dropout Operation and Bootstrap Voltage (BOOT)
      4. 6.3.4  Adjustable Output Voltage
      5. 6.3.5  Enable and Adjustable Undervoltage Lockout
      6. 6.3.6  External Soft Start
      7. 6.3.7  Switching Frequency and Synchronization (RT/SYNC)
      8. 6.3.8  Overcurrent and Short-Circuit Protection
      9. 6.3.9  Overvoltage Protection
      10. 6.3.10 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Pulse Skipping Mode
  8. 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 Output Voltage Set-Point
        2. 7.2.2.2 Switching Frequency
        3. 7.2.2.3 Output Inductor Selection
        4. 7.2.2.4 Output Capacitor Selection
        5. 7.2.2.5 Schottky Diode Selection
        6. 7.2.2.6 Input Capacitor Selection
        7. 7.2.2.7 Bootstrap Capacitor Selection
        8. 7.2.2.8 Soft-Start Capacitor Selection
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
  9. Device and Documentation Support
    1. 8.1 接收文档更新通知
    2. 8.2 支持资源
    3. 8.3 Trademarks
    4. 8.4 静电放电警告
    5. 8.5 术语表
  10. Revision History
  11. 10Mechanical, Packaging, and Orderable Information

Input Capacitor Selection

The LV14240 device requires high frequency input decoupling capacitors and a bulk input capacitor, depending on the application. The typical recommended value for the high frequency decoupling capacitor is 4.7 μF to 10 μF. TI recommends a high-quality ceramic capacitor type X5R or X7R with sufficiency voltage rating. To compensate the derating of ceramic capacitors, TI recommends a voltage rating of twice the maximum input voltage. Additionally, some bulk capacitance can be required, especially if the LV14240 circuit is not located within approximately 5 cm from the input voltage source. This capacitor is used to provide damping to the voltage spike due to the lead inductance of the cable or the trace. For this design, two 2.2-μF, X7R ceramic capacitors rated for 100 V are used. Use a 0.1 μF for high-frequency filtering and place as close as possible to the device pins.