SLVSFR1A August   2020  – May 2026 TPS25980

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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
    8. 6.8 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Undervoltage Protection (UVLO and UVP)
      2. 7.3.2 Overvoltage Protection (OVP)
      3. 7.3.3 Inrush Current, Overcurrent, and Short-Circuit Protection
        1. 7.3.3.1 Slew Rate and Inrush Current Control (dVdt)
        2. 7.3.3.2 Circuit Breaker
        3. 7.3.3.3 Short-Circuit Protection
      4. 7.3.4 Overtemperature Protection (OTP)
      5. 7.3.5 Analog Load Current Monitor (IMON)
      6. 7.3.6 Power Good (PG)
      7. 7.3.7 Load Detect/Handshake (LDSTRT)
    4. 7.4 Fault Response
    5. 7.5 Device Functional Modes
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application: Patient Monitoring System in Medical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Device Selection
        2. 8.2.2.2 Setting the Current Limit Threshold: RILIM Selection
        3. 8.2.2.3 Setting the Undervoltage Lockout Set Point
        4. 8.2.2.4 Selecting the Current Monitoring Resistor: RIMON
        5. 8.2.2.5 Setting the Output Voltage Ramp Time (TdVdt)
          1. 8.2.2.5.1 Case 1: Start-Up Without Load: Only Output Capacitance COUT Draws Current
          2. 8.2.2.5.2 Case 2: Start-Up With Load: Output Capacitance COUT and Load Draw Current
        6. 8.2.2.6 Setting the Load Handshake (LDSTRT) Delay
        7. 8.2.2.7 Setting the Transient Overcurrent Blanking Interval (tITIMER)
        8. 8.2.2.8 Setting the Auto-Retry Delay and Number of Retries
      3. 8.2.3 Application Curves
    3. 8.3 System Examples
      1. 8.3.1 Optical Module Power Rail Path Protection
        1. 8.3.1.1 Design Requirements
        2. 8.3.1.2 Device Selection
        3. 8.3.1.3 External Component Settings
        4. 8.3.1.4 Voltage Drop
        5. 8.3.1.5 Application Curves
      2. 8.3.2 Input Protection for 12V Rail Applications: PCIe Cards, Storage Interfaces and DC Fans
    4. 8.4 Power Supply Recommendations
      1. 8.4.1 Transient Protection
      2. 8.4.2 Output Short-Circuit Measurements
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

8.2.2.8 Setting the Auto-Retry Delay and Number of Retries

The time delay between retries can be programmed by selecting capacitor CRETRY_DLY on RETRY_DLY pin. The value of CRETRY_DLY to set a 100ms auto-retry delay can be calculated using Equation 25.

Equation 27. C R E T R Y _ D L Y ( p F ) = t R E T R Y _ D L Y ( μ s ) 46.83 - 4 p F = 2131.38 p F

Select closest available standard value: 2.2nF, 10%.

The number of auto-retry attempts can be set by a capacitor CNRETRY on the NRETRY pin using Equation 26

Equation 28. N R E T R Y = 4 × C N R E T R Y ( p F ) C R E T R Y _ D L Y ( p F ) + 4 p F

For this design example, the requirement is to retry 4 times after the device shuts down due to a fault. Since, the number of auto-retries can be adjusted in discrete steps as explained in Fault Response, select CNRETRY such that NRETRY is less than 4. Use Equation 27 to calculate CNRETRY.

Equation 29. C N R E T R Y ( p F ) < N R E T R Y × [ C R E T R Y _ D L Y ( p F ) + 4 p F ] 4 < 2204 P f

Select closest available standard value: 2.2nF, 10%.