SLVSBO1G July   2013  – June 2021 TPS54561

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
    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  Fixed Frequency PWM Control
      2. 7.3.2  Slope Compensation Output Current
      3. 7.3.3  Pulse Skip Eco-mode
      4. 7.3.4  Low Dropout Operation and Bootstrap Voltage (BOOT)
      5. 7.3.5  Error Amplifier
      6. 7.3.6  Adjusting the Output Voltage
      7. 7.3.7  Enable and Adjusting Undervoltage Lockout
      8. 7.3.8  Soft Start/Tracking Pin (SS/TR)
      9. 7.3.9  Sequencing
      10. 7.3.10 Constant Switching Frequency and Timing Resistor (RT/CLK) Pin)
      11. 7.3.11 Maximum Switching Frequency
      12. 7.3.12 Synchronization to RT/CLK Pin
      13. 7.3.13 Accurate Current Limit Operation
      14. 7.3.14 Power Good (PWRGD Pin)
      15. 7.3.15 Overvoltage Protection
      16. 7.3.16 Thermal Shutdown
      17. 7.3.17 Small Signal Model for Loop Response
      18. 7.3.18 Simple Small Signal Model for Peak Current Mode Control
      19. 7.3.19 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Buck Converter for 7-V to 60-V Input to 5-V at 5-A Output
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1  Custom Design with WEBENCH® Tools
          2. 8.2.1.2.2  Selecting the Switching Frequency
          3. 8.2.1.2.3  Output Inductor Selection (LO)
          4. 8.2.1.2.4  Output Capacitor
          5. 8.2.1.2.5  Catch Diode
          6. 8.2.1.2.6  Input Capacitor
          7. 8.2.1.2.7  Slow Start Capacitor
          8. 8.2.1.2.8  Bootstrap Capacitor Selection
          9. 8.2.1.2.9  Undervoltage Lockout Set Point
          10. 8.2.1.2.10 Output Voltage and Feedback Resistors Selection
          11. 8.2.1.2.11 Compensation
          12. 8.2.1.2.12 Power Dissipation Estimate
          13. 8.2.1.2.13 Safe Operating Area
          14. 8.2.1.2.14 Discontinuous Conduction Mode and Eco-mode Boundary
        3. 8.2.1.3 Application Curves
      2. 8.2.2 Inverting Buck-Boost Topology for Positive Input to Negative Output
      3. 8.2.3 Split-Rail Topology for Positive Input to Negative and Positive Output
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
    3. 10.3 Estimated Circuit Area
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Development Support
        1. 11.1.1.1 Custom Design with WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Support Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.1.1 Design Requirements

Figure 8-1 illustrates the design of a high frequency switching regulator using ceramic output capacitors. A few parameters must be known in order to start the design process. These requirements are typically determined at the system level. Calculations can be done with the aid of WEBENCH or the excel spreadsheet (SLVC452) located on the product page. This example is designed to the following known parameters:

Table 8-1 Design Parameters
PARAMETERVALUE
Output Voltage5 V
Transient response 1.25 A to 3.75 A load stepΔVOUT = 4 %
Maximum output current5 A
Input voltage12 V nom. 7 V to 60 V
Output voltage ripple0.5% of VOUT
Start input voltage (rising VIN)6.5 V
Stop input voltage (falling VIN)5 V