SLVSC61A November   2013  – October 2016 TPS54341

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  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 Typical Characteristics
  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  Low Dropout Operation and Bootstrap Voltage (BOOT)
      4. 7.3.4  Error Amplifier
      5. 7.3.5  Adjusting the Output Voltage
      6. 7.3.6  Enable and Adjusting Undervoltage Lockout
      7. 7.3.7  Soft-Start/Tracking Pin (SS/TR)
      8. 7.3.8  Sequencing
      9. 7.3.9  Constant Switching Frequency and Timing Resistor (RT/CLK Pin)
      10. 7.3.10 Accurate Current Limit Operation and Maximum Switching Frequency
      11. 7.3.11 Synchronization to RT/CLK Pin
      12. 7.3.12 Power Good (PWRGD Pin)
      13. 7.3.13 Overvoltage Protection
      14. 7.3.14 Thermal Shutdown
      15. 7.3.15 Small-Signal Model for Loop Response
      16. 7.3.16 Simple Small-Signal Model for Peak-Current-Mode Control
      17. 7.3.17 Small Signal Model for Frequency Compensation
    4. 7.4 Device Functional Modes
      1. 7.4.1 Pulse Skip Eco-mode
  8. Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1  Selecting the Switching Frequency
        2. 8.2.2.2  Output Inductor Selection (LO)
        3. 8.2.2.3  Output Capacitor
        4. 8.2.2.4  Catch Diode
        5. 8.2.2.5  Input Capacitor
        6. 8.2.2.6  Slow-Start Capacitor
        7. 8.2.2.7  Bootstrap Capacitor Selection
        8. 8.2.2.8  Undervoltage Lockout Set Point
        9. 8.2.2.9  Output Voltage and Feedback Resistors Selection
        10. 8.2.2.10 Compensation
        11. 8.2.2.11 Discontinuous Conduction Mode and Eco-mode Boundary
        12. 8.2.2.12 Estimated Circuit Area
        13. 8.2.2.13 Power Dissipation Estimate
      3. 8.2.3 Application Curves
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Receiving Notification of Documentation Updates
    4. 11.4 Community Resources
    5. 11.5 Trademarks
    6. 11.6 Electrostatic Discharge Caution
    7. 11.7 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

パッケージ・オプション

メカニカル・データ(パッケージ|ピン)
サーマルパッド・メカニカル・データ
発注情報

Layout

Layout Guidelines

Layout is a critical portion of good power supply design. There are several signal paths that conduct fast changing currents or voltages that can interact with stray inductance or parasitic capacitance to generate noise or degrade performance. To reduce parasitic effects, the VIN pin should be bypassed to ground with a low ESR ceramic bypass capacitor with X5R or X7R dielectric. Care should be taken to minimize the loop area formed by the bypass capacitor connections, the VIN pin, and the anode of the catch diode. See Figure 68 for a PCB layout example. The GND pin should be tied directly to the power pad under the IC and the power pad.

The power pad should be connected to internal PCB ground planes using multiple vias directly under the IC. The SW pin should be routed to the cathode of the catch diode and to the output inductor. Because the SW connection is the switching node, the catch diode and output inductor should be located close to the SW pins, and the area of the PCB conductor minimized to prevent excessive capacitive coupling. For operation at full rated load, the top side ground area must provide adequate heat dissipating area. The RT/CLK pin is sensitive to noise so the RT resistor should be located as close as possible to the IC and routed with minimal lengths of trace. The additional external components can be placed approximately as shown. It may be possible to obtain acceptable performance with alternate PCB layouts, however this layout has been shown to produce good results and is meant as a guideline.

Layout Example

TPS54341 layout_slvsc57.gif Figure 68. PCB Layout Example