SNAA416A April   2025  – June 2025 LMK3C0105-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Test Setup
    1. 2.1 Board Variation Summary Table
    2. 2.2 Schematics
    3. 2.3 Layouts
    4. 2.4 Stack-Up
  6. 3CISPR-25
    1. 3.1 CISPR-25 Summary
    2. 3.2 CISPR-25 Results
      1. 3.2.1 Monopole
      2. 3.2.2 Bi-Conical
      3. 3.2.3 Log-Periodic
      4. 3.2.4 Horn
  7. 4CISPR-32
    1. 4.1 CISPR-32 Summary
    2. 4.2 CISPR-32 Results
  8. 5Summary
  9. 6References
  10. 7Revision History

5 Summary

Overall, Variant 2 performed best due to the additional GND vias creating a strong GND for the circuit. When designing PCBs for EMI performance, consider using common tactics such as GND vias and SSC.

CISPR-25

At 3.3V, the LMK3C0105-Q1 with no shielding vias and 8+ in trace length passes Class 5 standards for all bands except for TV Band IV (470MHz to 944MHz), Analouge UHF (380MHz to 512MHz and 820MHz to 960MHz), GPS L1 (1567.42MHz to 1583.42MHz), and GPS L5 (1156.45MHz to 1196.45MHz). For best performance, use of additional GND vias and SSC is recommended.

At 1.8V, the LMK3C0105-Q1 with no shielding vias and 8+ in trace length passes Class 5 standards for all bands except for TV Band IV, GPS L1, and GPS L5. For best performance, use of additional GND vias or SSC is highly recommended.

CISPR-32

The LMK3C0105-Q1 performed similarly to XOs across all frequency bands and passes CISPR-32 Class B across 30MHz to 3000MHz with no shielding vias and 8+ in trace length with both 1.8V and 3.3V supply voltage.