SLVS762C June   2007  – July 2015 TPS62242

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Options
  6. 6 Pin Configuration and 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 Undervoltage Lockout
      2. 8.3.2 Mode Selection
      3. 8.3.3 Enable
      4. 8.3.4 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Soft Start
      2. 8.4.2 Power Save Mode
      3. 8.4.3 100% Duty Cycle Low Dropout Operation
      4. 8.4.4 Short-Circuit Protection
  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 Output Voltage Setting
        2. 9.2.2.2 Output Filter Design (Inductor and Output Capacitor)
          1. 9.2.2.2.1 Inductor Selection
          2. 9.2.2.2.2 Output Capacitor Selection
          3. 9.2.2.2.3 Input Capacitor Selection
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 TPS62240, Adjustable Output Voltage 1.8 V
      2. 9.3.2 TPS62243, Fixed Output Voltage 1.8 V
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
    2. 12.2 Related Links
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

11 Layout

11.1 Layout Guidelines

As for all switching power supplies, the layout is an important step in the design. Proper function of the device demands careful attention to PCB layout. Care must be taken in board layout to get the specified performance. If the layout is not carefully done, the regulator could show poor line and/or load regulation, and additional stability issues as well as EMI problems. It is critical to provide a low inductance, impedance ground path. Therefore, use wide and short traces for the main current paths. The input capacitor should be placed as close as possible to the IC pins as well as the inductor and output capacitor.

Connect the GND pin of the device to the PowerPAD™ land of the PCB and use this pad as a star point. Use a common power GND node and a different node for the signal GND to minimize the effects of ground noise. Connect these ground nodes together to the PowerPAD land (star point) underneath the IC. Keep the common path to the GND pin, which returns the small signal components, and the high current of the output capacitors as short as possible to avoid ground noise. The FB line should be connected right to the output capacitor and routed away from noisy components and traces (for example, the SW line).

11.2 Layout Examples

TPS62240 TPS62242 TPS62243 layout_lvs763.gifFigure 30. Suggested Layout for Fixed Output Voltage Options
TPS62240 TPS62242 TPS62243 layout_lvs762.gifFigure 31. Suggested Layout for Adjustable Output Voltage Version