SLVSEJ2A February   2018  – April 2018 TPSM84424

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Transient Response
  4. 4 Revision History
  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
    6. 6.6 Switching Characteristics
    7. 6.7 Typical Characteristics (VIN = 12 V)
    8. 6.8 Typical Characteristics (VIN = 5 V)
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Adjusting the Output Voltage
      2. 7.3.2  Switching Frequency (RT)
      3. 7.3.3  Synchronization (CLK)
      4. 7.3.4  Output On/Off Enable (EN)
      5. 7.3.5  Input Capacitor Selection
      6. 7.3.6  Output Capacitor Selection
      7. 7.3.7  TurboTrans (TT)
        1. 7.3.7.1 Low-ESR Output Capacitors
        2. 7.3.7.2 Transient Response
          1. 7.3.7.2.1 Transient Waveforms (VIN = 12 V)
      8. 7.3.8  Undervoltage Lockout (UVLO)
      9. 7.3.9  Soft Start (SS/TR)
      10. 7.3.10 Sequencing (SS/TR)
      11. 7.3.11 Power Good (PGOOD)
      12. 7.3.12 Safe Start-up into Pre-Biased Outputs
      13. 7.3.13 Overcurrent Protection
      14. 7.3.14 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Active Mode
      2. 7.4.2 Shutdown Mode
  8. 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 Output Voltage Setpoint
        3. 8.2.2.3 Setting the Switching Frequency
        4. 8.2.2.4 Input Capacitors
        5. 8.2.2.5 Output Capacitors
        6. 8.2.2.6 TurboTrans Resistor
        7. 8.2.2.7 Application Waveforms
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
    3. 10.3 EMI
      1. 10.3.1 EMI Plots
    4. 10.4 Package Specifications
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Development Support
      1. 11.2.1 Custom Design With WEBENCH® Tools
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

7.3.4 Output On/Off Enable (EN)

The EN pin provides electrical ON/OFF control of the device. Once the EN pin voltage exceeds the threshold voltage, the device starts operation. If the EN pin voltage is pulled below the threshold voltage, the regulator stops switching and enters low operating current state. The EN pin has an internal pullup current source allowing the user to float the EN pin for enabling the device.

If an application requires controlling the EN pin, either drive it directly with a logic input or use an open drain/collector device to interface with the pin. Applying a low voltage to the enable control (EN) pin disables the output of the supply, shown in Figure 12. When the EN pin voltage exceeds the threshold voltage, the supply executes a soft-start power-up sequence, as shown in Figure 13.

TPSM84424 EN_OFF.gifFigure 12. Enable Turnoff
TPSM84424 EN_ON.gifFigure 13. Enable Turnon