SLUP408 February   2022 LM25149-Q1 , LM61460-Q1 , LM61495-Q1 , LMQ61460-Q1


  1. Introduction
  2. Defining EMI
  3. What Causes EMI in a Switched-Mode DC/DC Regulator?
  4. Existing Passive EMI Filtering Techniques
  5. Passive Filter Limitations
  6. AEF
  7. Spread Spectrum
  8. DRSS
  9. True Slew-Rate Control
  10. 10HotRod™ Package Technology
  11. 11Optimized Package and Pinout
  12. 12Integrated Capacitors
  13. 13Conclusions
  14. 14References
  15. 15Important Notice


The electrification of everything has introduced electronics to many applications in the world around us. Communications, transportation, factory automation and control, personal electronics, and health care are the most recognizable examples of electronics integration, while software innovation relies on the underlying hardware infrastructure.

With more electronic and computer systems used in smaller and tighter spaces, EMI becomes an increasing focus for system design. Switched-mode power supplies (SMPSs) are the most efficient way to power electronic systems, but they generate a significant amount of EMI. Increased switching speeds and switching frequencies result in higher power density but also tend to make EMI worse.