ZHCSIT5B september   2018  – august 2023 LM5164

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Revision History
  6. 5 Pin Configuration and Functions
  7. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Control Architecture
      2. 7.3.2  Internal VCC Regulator and Bootstrap Capacitor
      3. 7.3.3  Regulation Comparator
      4. 7.3.4  Internal Soft Start
      5. 7.3.5  On-Time Generator
      6. 7.3.6  Current Limit
      7. 7.3.7  N-Channel Buck Switch and Driver
      8. 7.3.8  Synchronous Rectifier
      9. 7.3.9  Enable/Undervoltage Lockout (EN/UVLO)
      10. 7.3.10 Power Good (PGOOD)
      11. 7.3.11 Thermal Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 Sleep Mode
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Switching Frequency (RRON)
        3. 8.2.2.3 Buck Inductor (LO)
        4. 8.2.2.4 Output Capacitor (COUT)
        5. 8.2.2.5 Input Capacitor (CIN)
        6. 8.2.2.6 Type-3 Ripple Network
      3. 8.2.3 Application Curves
  10. 9 Power Supply Recommendations
  11. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Compact PCB Layout for EMI Reduction
      2. 10.1.2 Feedback Resistors
    2. 10.2 Layout Example
  12. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 第三方产品免责声明
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Related Documentation
    3. 11.3 接收文档更新通知
    4. 11.4 支持资源
    5. 11.5 Trademarks
    6. 11.6 静电放电警告
    7. 11.7 术语表
  13. 12Mechanical, Packaging, and Orderable Information

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7.3.9 Enable/Undervoltage Lockout (EN/UVLO)

The LM5164 contains a dual-level EN/UVLO circuit. When the EN/UVLO voltage is below 1.1 V (typical), the converter is in a low-current shutdown mode and the input quiescent current (IQ) is dropped down to 3 µA. When the voltage is greater than 1.1 V but less than 1.5 V (typical), the converter is in standby mode. In standby mode, the internal bias regulator is active while the control circuit is disabled. When the voltage exceeds the rising threshold of 1.5 V (typical), normal operation begins. Install a resistor divider from VIN to GND to set the minimum operating voltage of the regulator. Use Equation 13 and Equation 14 to calculate the input UVLO turnon and turnoff voltages, respectively.

Equation 13. GUID-B4D836E1-3103-443D-95D4-DD3766BAB2C8-low.gif
Equation 14. GUID-FE5A9F55-EB2E-45AB-BBEF-F21915F52DA0-low.gif

TI recommends selecting RUV1 in the range of 1 MΩ for most applications. A larger RUV1 consumes less DC current, which is mandatory if light-load efficiency is critical. If input UVLO is not required, the power-supply designer can either drive EN/UVLO as an enable input driven by a logic signal or connect it directly to VIN. If EN/UVLO is directly connected to VIN, the regulator begins switching as soon as the internal bias rails are active.