ZHCSI25 April   2018 LMV7239-Q1

PRODUCTION DATA.  

  1. 1 特性
  2. 2 应用
  3. 3 说明
    1.     Device Images
      1.      电源电流与电源电压间的关系
      2.      传播延迟与过驱动
  4. 4 修订历史记录
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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, 2.7 V
    6. 6.6 Electrical Characteristics, 5 V
    7. 6.7 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Input Stage
      2. 7.3.2 Output Stage: LMV7239-Q1
    4. 7.4 Device Functional Modes
      1. 7.4.1 Capacitive and Resistive Loads
      2. 7.4.2 Noise
      3. 7.4.3 Hysteresis
        1. 7.4.3.1 Inverting Comparator With Hysteresis
        2. 7.4.3.2 Non-Inverting Comparator With Hysteresis
      4. 7.4.4 Zero Crossing Detector
        1. 7.4.4.1 Zero Crossing Detector With Hysteresis
      5. 7.4.5 Threshold Detector
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Square Wave Oscillator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Crystal Oscillator
      3. 8.2.3 Infrared (IR) Receiver
      4. 8.2.4 Window Detector
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11器件和文档支持
    1. 11.1 器件支持
      1. 11.1.1 开发支持
    2. 11.2 文档支持
      1. 11.2.1 相关文档
    3. 11.3 接收文档更新通知
    4. 11.4 社区资源
    5. 11.5 商标
    6. 11.6 静电放电警告
    7. 11.7 术语表
  12. 12机械、封装和可订购信息

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

7.4.4.1 Zero Crossing Detector With Hysteresis

To improve switching times and centering the input threshold to ground a small amount of positive feedback is added to the circuit. Voltage divider R4 and R5 establishes a reference voltage, V1, at the positive input. By making the series resistance, R1 plus R2 equal to R5, the switching condition, V1 = V2, will be satisfied when VIN = 0.

The positive feedback resistor, R6, is made very large with respect to R5 || R6 = 2000 R5). The resultant hysteresis established by this network is very small (ΔV1< 10 mV) but it is sufficient to insure rapid output voltage transitions.

Diode D1 is used to ensure that the inverting input terminal of the comparator never goes below approximately −100 mV. As the input terminal goes negative, D1 will forward bias, clamping the node between R1 and R2 to approximately −700 mV. This sets up a voltage divider with R2 and R3 preventing V2 from going below ground. The maximum negative input overdrive is limited by the current handling ability of D1.

LMV7239-Q1 20201329.gifFigure 22. Zero Crossing Detector With Hysteresis