SLVAFJ3 september   2023 LM5177 , LM51772

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Importance of DC-DC Power Supply Layout
  5. 2Steps for a Good Layout
    1. 2.1 Identifying Critical Circuit Paths
    2. 2.2 Optimizing Hot Loops in the Power Stage
    3. 2.3 Separating Differential Sense Lines From Power Planes
      1. 2.3.1 Using Net Ties to Separate Routing
    4. 2.4 Routing Gate-Drive and Return Paths
    5. 2.5 Controller Layout
    6. 2.6 Separate AGND and PGND
    7. 2.7 Thermal Vias
  6. 3Tips for Layout Optimization
  7. 4Layout Example
  8. 5Summary
  9. 6References

1 Importance of DC-DC Power Supply Layout

The PCB layout design is very important when designing a switching power supply. If the PCB layout is inappropriate, the power supply performance can be hindered, up to a damage of the converter. Often, issues with switching power supply prototypes start with the PCB layout.

Poor layout increases the parasitic inductance, capacitance and resistance within the circuit. The poor layout can increase noise pickup between different parts of the circuit, and increase thermal stresses within the regulator.

This application note provides a guideline example for our new LM5177 wide Vin bidirectional 4-switch buck-boost regulator. Under the guidance of this application note, the customers can achieve stable operation, and good thermal and low EMI performance. The main content includes identification of the critical switching loops, optimizing the hot loops, separating differential sense lines from power planes, AGND and PGND connection.