SNAA408 April   2025 LMK3H0102

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Output Recommendations
    1. 2.1 Differential vs. Single-Ended
    2. 2.2 Slew Rate
    3. 2.3 Spread Spectrum Clocking
  6. 3PCB Design
    1. 3.1 Stackup
    2. 3.2 Power Filtering
    3. 3.3 Avoid Bottlenecking
    4. 3.4 Strategic Via Placements
      1. 3.4.1 Distributing Power Concentrations
        1. 3.4.1.1 Via Sizes
        2. 3.4.1.2 Pads and Pours
      2. 3.4.2 Shielding and Stitching Vias
  7. 4Minimize Possible Antennas
    1. 4.1 Stubs
    2. 4.2 Net Pours
  8. 5Summary
  9. 6References

Abstract

Electromagnetic interference (EMI) is any unwanted interference in an electrical circuit caused by an external source. EMI can be categorized as conducted or radiated. Conducted EMI is a form of conduction coupling caused by parasitic impedance, power, and ground connections. Radiated EMI is the coupling of unwanted signals from radio transmission. This application note discusses how to minimize radiated EMI from clocking devices through frequency planning and printed circuit board (PCB) design.