SLVSDK7C April   2017  – February 2020 TPS22971

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  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 DC Characteristics
    8. 6.8 Typical AC Characteristics
  7. 7 Parameter Measurement Information
  8. 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 Controlled Turn-On
      3. 8.3.3 Power Good (PG)
      4. 8.3.4 Quick Output Discharge (QOD)
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Thermal Consideration
      2. 9.1.2 PG Pull Up Resistor
      3. 9.1.3 Power Sequencing
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Maximum Voltage Drop and On-Resistance
        2. 9.2.2.2 Managing Inrush Current
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.2.2 Managing Inrush Current

When the switch is enabled, the output capacitors must be charged up from 0 V to VIN. This charge arrives in the form of inrush current. Given a load capacitance (CL) of 33 μF, an input voltage (VIN) of 3.6V and a maximum inrush (IINRUSH) of 630 mA, use Equation 12 and Equation 13 to solve for Slew Rate (SR).

Equation 12. TPS22971 tps22971x-equation-12.gif
Equation 13. TPS22971 tps22971x-equation-13.gif

Now that the desired slew rate has been calculated, use SR and VIN in in Equation 14 to calculate a CT capacitance value.

Equation 14. TPS22971 tps22971x-equation-14.gif

A capacitance value of 1007pF is a non-standard value therefore a 1000 pF CT capacitance is used moving forward.

The calculated CT value can be used with Equation 2 and Equation 4 to determine tON and tPG,ON, respectively as shown in Equation 15 and Equation 16.

Equation 15. TPS22971 tps22971x-equation-15.gif
Equation 16. TPS22971 tps22971x-equation-16.gif