ZHCSHL1A September   2017  – February 2018 TPS22917

PRODUCTION DATA.  

  1. 特性
  2. 应用
  3. 说明
    1.     Device Images
      1.      简化原理图
  4. 修订历史记录
  5. Pin Configuration and Functions
    1.     Pin Functions
  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 Switching Characteristics
    7. 6.7 Typical Characteristics
      1. 6.7.1 Typical Electrical Characteristics
      2. 6.7.2 Typical Switching Characteristics
  7. Parameter Measurement Information
    1. 7.1 Test Circuit and Timing Waveforms Diagrams
  8. Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 On and Off Control
      2. 8.3.2 Turn On Time (tON) and Adjustable Slew Rate (CT)
      3. 8.3.3 Fall Time (tFALL) and Quick Output Discharge (QOD)
        1. 8.3.3.1 QOD when System Power is Removed
    4. 8.4 Full-Time Reverse Current Blocking
    5. 8.5 Device Functional Modes
  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 Limiting Inrush Current
        2. 9.2.2.2 Application Curves
        3. 9.2.2.3 Setting Fall Time for Shutdown Power Sequencing
        4. 9.2.2.4 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
    3. 11.3 Thermal Considerations
  12. 12器件和文档支持
    1. 12.1 接收文档更新通知
    2. 12.2 社区资源
    3. 12.3 商标
    4. 12.4 静电放电警告
    5. 12.5 Glossary
  13. 13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

Turn On Time (tON) and Adjustable Slew Rate (CT)

A capacitor to VIN on the CT pin sets the slew rate of VOUT. The CT capacitor voltage will ramp until shortly after the switch is turned on and VOUT becomes stable.

Leaving the CT pin open will result in the highest slew rate and fastest turn on time. These values can be found in the Switching Characteristics Table. For slower slew rates the required CT capacitor can be found using Equation 1:

Equation 1. CT = (Slew Rate) ÷ SRON

where

  • Slew Rate = Desired slew rate (mV/us)
  • CT = The capacitance value on the CT pin (pF)
  • SRON = Slew Rate Constant from Table ((mV/µs) × pF)

The total turn on time has a direct correlation to the output slew rate. The fastest turn on times (tON), with CT pin open, can be found in the Switching Characteristics. For slower slew rates, the resulting turn on time can be found with Equation 2:

Equation 2. Turn On time = CT × tON

where

  • Turn On Time = Total Time from Enable until VOUT rises to 90% of VIN (µs)
  • CT = The capacitance value on the CT pin (pF)
  • tON = Turn On Time Constant (µs/pF)