SLVSGU5A April   2022  – July 2022 TPS22811

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Timing Requirements
    7. 6.7 Switching Characteristics
      1.      14
    8. 6.8 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 Undervoltage Lockout (UVLO and UVP)
      2. 7.3.2 Overvoltage Lockout (OVLO)
      3. 7.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 7.3.3.1 Slew Rate (dVdt) and Inrush Current Control
        2. 7.3.3.2 Short-Circuit Protection
        3. 7.3.3.3 Active Current Limiting During Start-Up
      4. 7.3.4 Analog Load Current Monitor
      5. 7.3.5 Overtemperature Protection (OTP)
      6. 7.3.6 Fault Response
      7. 7.3.7 Power-Good Indication (PG)
      8. 7.3.8 Quick Output Discharge (QOD)
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Single Device, Self-Controlled
      2. 8.1.2 Parallel Operation
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Setting Undervoltage and Overvoltage Thresholds
        2. 8.2.2.2 Setting Output Voltage Rise Time (tR)
        3. 8.2.2.3 Setting Power-Good Assertion Threshold
        4. 8.2.2.4 Setting Analog Current Monitor Voltage (IMON) Range
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
    1. 9.1 Transient Protection
    2. 9.2 Output Short-Circuit Measurements
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.3.1 Slew Rate (dVdt) and Inrush Current Control

During hot-plug events or while trying to charge a large output capacitance at start-up, there can be a large inrush current. If the inrush current is not managed properly, it can damage the input connectors and cause the system power supply to droop leading to unexpected restarts elsewhere in the system. The inrush current during turn on is directly proportional to the load capacitance and rising slew rate. Equation 3 can be used to find the slew rate (SR) required to limit the inrush current (IINRUSH) for a given load capacitance (COUT):

Equation 3. S R   V m s = I I N R U S H   ( m A ) C O U T   µ F

A capacitor can be connected to the dVdt pin to control the rising slew rate and lower the inrush current during turn on. Use Equation 4 to calculate the required CdVdt capacitance to produce a given slew rate.

Equation 4. CdVdt pF=3300SR Vms

The fastest output slew rate is achieved by leaving the dVdt pin open.

Note:

For CdVdt > 10 nF, TI recommends to add a 100-Ω resistor in series with the capacitor on the dVdt pin.