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

6.1 Overview

The TPS5420 is a 36V, 2A, step-down (buck) regulator with an integrated, high-side, N-Channel MOSFET. These devices implement constant-frequency voltage-mode control with voltage feed-forward for improved line regulation and line transient response. Internal compensation reduces design complexity and external component count.

The integrated 110mΩ high-side MOSFET supports high-efficiency power-supply designs capable of delivering 2A of continuous current to a load. The gate-drive bias voltage for the integrated high-side MOSFET is supplied by a bootstrap capacitor connected from the BOOT to PH pins. The TPS5420 reduces the external component count by integrating the bootstrap recharge diode.

The TPS5420 has a default input start-up voltage of 5.3V typical. The ENA pin can be used to disable the TPS5420 reducing the supply current to 18µA. An internal 1.5MΩ pullup resistor enables operation when the ENA pin is left floating. Do not connect a resistor from the ENA pin to ground. The TPS5420 includes an internal slow-start circuit that slows the output rise time during start up to reduce in rush current and output voltage overshoot.

The minimum output voltage is the internal 1.221V feedback reference. Output overvoltage transients are minimized by an Overvoltage Protection (OVP) comparator. When the OVP comparator is activated, the high-side MOSFET is turned off and remains off until the output voltage is less than 112.5% of the desired output voltage.

Internal cycle-by-cycle overcurrent protection limits the peak current in the integrated high-side MOSFET. For continuous overcurrent fault conditions the TPS5420 enters hiccup mode overcurrent limiting. Thermal protection protects the device from overheating.