SLVS642G April   2006  – April 2026 TPS5420

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information 
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1  Oscillator Frequency
      2. 6.3.2  Voltage Reference
      3. 6.3.3  Enable (ENA) and Internal Slow Start
      4. 6.3.4  Undervoltage Lockout (UVLO)
      5. 6.3.5  Boost Capacitor (BOOT)
      6. 6.3.6  Output Feedback (VSENSE)
      7. 6.3.7  Internal Compensation
      8. 6.3.8  Voltage Feed Forward
      9. 6.3.9  Pulse-Width-Modulation (PWM) Control
      10. 6.3.10 Overcurrent Limiting
      11. 6.3.11 Overvoltage Protection
      12. 6.3.12 Thermal Shutdown
    4. 6.4 Device Functional Modes
      1. 6.4.1 Minimum Input Voltage
      2. 6.4.2 ENA Control
  8. 7 Application and Implementation
    1. 7.1 Application Information
    2. 7.2 Typical Application
      1. 7.2.1 Application Circuits
        1. 7.2.1.1 Design Requirements
        2. 7.2.1.2 Detailed Design Procedure
          1. 7.2.1.2.1 Switching Frequency
          2. 7.2.1.2.2 Input Capacitors
          3. 7.2.1.2.3 Output Filter Components
            1. 7.2.1.2.3.1 Inductor Selection
            2. 7.2.1.2.3.2 Capacitor Selection
            3.         43
            4.         44
          4. 7.2.1.2.4 Output Voltage Setpoint
          5. 7.2.1.2.5 Boot Capacitor
          6. 7.2.1.2.6 Catch Diode
          7. 7.2.1.2.7 Advanced Information
            1. 7.2.1.2.7.1 Output Voltage Limitations
            2. 7.2.1.2.7.2 Internal Compensation Network
            3. 7.2.1.2.7.3 Thermal Calculations
          8. 7.2.1.2.8 Output Filter Component Selection
          9. 7.2.1.2.9 External Compensation Network
        3. 7.2.1.3 Application Curves
      2. 7.2.2 Additional Circuits
      3. 7.2.3 Circuit Using Ceramic Output Filter Capacitors
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 PCB Layout Guidelines
      2. 7.4.2 Layout Example
  9. 8 Device and Documentation Support
    1. 8.1 Documentation Support
      1. 8.1.1 Related Documentation
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information
7.2.1.2.7.3 Thermal Calculations

The following formulas show how to estimate the device power dissipation under continuous conduction mode operations. They must not be used if the device is working at light loads in the discontinuous conduction mode.

Conduction Loss: Pcon = IOUT2 x RDS(on) x VOUT / VIN

Switching Loss: Psw = VIN x IOUT x 0.01

Quiescent Current Loss: Pq = VIN x 0.01

Total Loss: Ptot = Pcon + Psw + Pq

Given TA => Estimated Junction Temperature: TJ = TA + Rth x Ptot

Given TJMAX = 125°C => Estimated Maximum Ambient Temperature: TAMAX = TJMAX  – Rth x Ptot