ZHCSN39A February   2020  – November 2021 LM61480 , LM61495 , LM62460

PRODUCTION DATA  

  1. 1 特性
  2. 2 应用
  3. 3 说明
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
  7. 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 Timing Characteristics
    7. 7.7 Switching Characteristics
    8. 7.8 System Characteristics
    9. 7.9 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Output Voltage Selection
      2. 8.3.2  Enable EN Pin and Use as VIN UVLO
      3. 8.3.3  SYNC/MODE Uses for Synchronization
      4. 8.3.4  Clock Locking
      5. 8.3.5  Adjustable Switching Frequency
      6. 8.3.6  RESET Output Operation
      7. 8.3.7  Internal LDO, VCC UVLO, and BIAS Input
      8. 8.3.8  Bootstrap Voltage and VCBOOT-UVLO (CBOOT Pin)
      9. 8.3.9  Adjustable SW Node Slew Rate
      10. 8.3.10 Spread Spectrum
      11. 8.3.11 Soft Start and Recovery From Dropout
      12. 8.3.12 Overcurrent and Short Circuit Protection
      13. 8.3.13 Hiccup
      14. 8.3.14 Thermal Shutdown
    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 Peak Current Mode Operation
        2. 8.4.3.2 Auto Mode Operation
          1. 8.4.3.2.1 Diode Emulation
        3. 8.4.3.3 FPWM Mode Operation
        4. 8.4.3.4 Minimum On-time (High Input Voltage) Operation
        5. 8.4.3.5 Dropout
        6. 8.4.3.6 Recovery from Dropout
        7. 8.4.3.7 Other Fault Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Choosing the Switching Frequency
        2. 9.2.2.2  Setting the Output Voltage
        3. 9.2.2.3  Inductor Selection
        4. 9.2.2.4  Output Capacitor Selection
        5. 9.2.2.5  Input Capacitor Selection
        6. 9.2.2.6  BOOT Capacitor
        7. 9.2.2.7  BOOT Resistor
        8. 9.2.2.8  VCC
        9. 9.2.2.9  CFF and RFF Selection
        10. 9.2.2.10 RSPSP Selection
        11. 9.2.2.11 RT Selection
        12. 9.2.2.12 RMODE Selection
        13. 9.2.2.13 External UVLO
        14. 9.2.2.14 Maximum Ambient Temperature
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ground and Thermal Considerations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 第三方米6体育平台手机版_好二三四免责声明
    2. 12.2 接收文档更新通知
    3. 12.3 支持资源
    4. 12.4 Trademarks
    5. 12.5 术语表
    6. 12.6 Electrostatic Discharge Caution
  13. 13Mechanical, Packaging, and Orderable Information

封装选项

机械数据 (封装 | 引脚)
散热焊盘机械数据 (封装 | 引脚)
订购信息

8.3.5 Adjustable Switching Frequency

The RT pin is configurable. This pin can be tied to VCC for 400-kHz operation, grounded for 2.2-MHz operation, or a resistor to AGND can be used to set an adjustable operating frequency. See Figure 8-6 for resistor values. Note that if a resistor value falls outside of the recommended range, it can cause the LM6x4xx to revert to 400 kHz or 2.2 MHz. Do not apply a pulsed signal to this pin to force synchronization. If synchronization is needed, see the SYNC/MODE pin in Section 8.3.3.

Equation 3. RT (kΩ) = (16.4 / fSW (MHz)) - 0.633

For example, for fSW = 400 kHz, RT = (16.4 / 0.4) - 0.633 = 40.37, so a 40.2-kΩ resistor is selected as the closest choice.

Figure 8-6 Setting Clock Frequency
千亿体育app官网登录(中国)官方网站IOS/安卓通用版/手机APP | 米乐app下载官网（中国）|ios|Android/通用版APP最新版 | 米乐|米乐·M6（中国大陆）官方网站 | 千亿体育登陆地址 | 华体会体育（中国）HTH·官方网站 | 千赢qy国际_全站最新版千赢qy国际V6.2.14安卓/IOS下载 | 18新利网v1.2.5|中国官方网站 | bob电竞真人（中国官网）安卓/ios苹果/电脑版【1.97.95版下载】 | 千亿体育app官方下载(中国)官方网站IOS/安卓/手机APP下载安装 |