ZHCSHM2D June   2018  – April 2025 TPS746-Q1

PRODUCTION DATA  

  1.   1
  2. 1 特性
  3. 2 应用
  4. 3 说明
  5. 4 Pin Configuration and Functions
  6. 5 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 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagrams
    3. 6.3 Feature Description
      1. 6.3.1 Undervoltage Lockout (UVLO)
      2. 6.3.2 Shutdown
      3. 6.3.3 Foldback Current Limit
      4. 6.3.4 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Normal Operation
      2. 6.4.2 Dropout Operation
      3. 6.4.3 Disabled
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Adjustable Device Feedback Resistors
      2. 7.1.2 Input and Output Capacitor Selection
      3. 7.1.3 Dropout Voltage
      4. 7.1.4 Exiting Dropout
      5. 7.1.5 Reverse Current
      6. 7.1.6 Power Dissipation (PD)
      7. 7.1.7 Power-Good Function
      8. 7.1.8 Feed-Forward Capacitor (CFF)
      9. 7.1.9 Start-Up Sequencing
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1 Input Current
        2. 7.2.2.2 Thermal Dissipation
      3. 7.2.3 Application Curve
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Examples
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Device Nomenclature
    2. 8.2 Documentation Support
      1. 8.2.1 Related Documentation
    3. 8.3 接收文档更新通知
    4. 8.4 支持资源
    5. 8.5 Trademarks
    6. 8.6 静电放电警告
    7. 8.7 术语表
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

6.3.2 Shutdown

The enable pin (EN) is active high. Enable the device by forcing the EN pin to exceed VEN(HI). Turn off the device by forcing the EN pin to drop below VEN(LO). If shutdown capability is not required, connect EN to IN.

The TPS746-Q1 has an internal pulldown MOSFET that connects an RPULLDOWN resistor to ground when the device is disabled. The discharge time after disabling depends on the output capacitance (COUT) and the load resistance (RL) in parallel with the pulldown resistor (RPULLDOWN). Equation 1 calculates the time constant:

Equation 1. τ = ( RPULLDOWN × RL) / (RPULLDOWN + RL)