SLUS907K January   2009  – June 2019 TPS2421-1 , TPS2421-2

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 CT
      2. 8.3.2 FLT
      3. 8.3.3 GND
      4. 8.3.4 ISET
      5. 8.3.5 VIN
      6. 8.3.6 VOUT
      7. 8.3.7 PG
    4. 8.4 Device Functional Modes
      1. 8.4.1 Startup
      2. 8.4.2 Maximum Allowable Load to Ensure Successful Startup
        1. 8.4.2.1 Enable Pin Considerations
        2. 8.4.2.2 Fault Timer
        3. 8.4.2.3 Normal Operation
        4. 8.4.2.4 Startup into a Short
      3. 8.4.3 Shutdown Modes
        1. 8.4.3.1 Hard Overload - Fast Trip
        2. 8.4.3.2 Overcurrent Shutdown
    5. 8.5 Programming
      1. 8.5.1 Fault (ISET) and Current-Limit (ILIM) Thresholds
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Transient Protection
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
    1. 10.1 PowerPad™
  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 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resource
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

9.2.2 Detailed Design Procedure

1. Calculate maximum RRSET to ensure that minimum ISET is above maximum operating load current using Equation 11 as shown below in Equation 14.
Equation 14. TPS2421-1 TPS2421-2 Eq18_rsetmax_lus907.gif
● Choose a standard 1% value below RRSET,max for RRSET = 80.6 kΩ
● ISET,min = 2.15 A using Equation 8 meets the maximum operating current requirement of 2.1 A without starting the fault timer during maximum steady state operation for RRSET = 80.6 kΩ, 1%.
● ISET,max = 4.359 A using Equation 9 for RRSET = 80.6 Ω, 1%.
2. Calculate minimum and maximum ILIM.
● ILIM,min = 2.792 A and ILIM,max = 4.359 A using Equation 12 and Equation 13 for RRSET = 80.6 kΩ, 1%.
3. Minimum RLOAD at startup using Equation 6 is 12 Ω. Because RLOAD = 15 Ω is present during circuit startup, use tON = 15 ms from Table 2 for CLOAD = 220 µF and RLOAD = 15 Ω.
● Calculate CCT = 0.48 µF including CLOAD and CCT tolerances (CLOAD_TOL = 20% and CCT_TOL = 10%) using Equation 15.
Equation 15. TPS2421-1 TPS2421-2 Eq19_CCT_lus907.gif