Conformal coatings are often applied to printed circuit boards to protect the board and its components from environmental factors like moisture, chemicals, and vibration. The impact of a conformal coating on crosstalk and radiated emissions was studied in the following paper. Two coating materials were characterized in terms of their permittivity and permeability. The impact of the conformal coating was evaluated based on the crosstalk between microstrip traces, the radiated emissions from a switch-mode power supply (SMPS), and on coupling from an EMI filter to nearby components. The coatings increased crosstalk between microstrip traces by up to 5 ~ 6 dB, and increased radiated emissions from the SMPS by up to 8 dB. While the coating did not affect the performance of the EMI filter, a 5.5 dB increase in coupling was observed from the filter to nearby components. These effects should be considered if pre-compliance testing is performed before the coatings are applied.
H. Manoharan et al., "Influence of Conformal Coatings on the Emc Performance of a Printed Circuit Board," 2022 Asia-Pacific International Symposium on Electromagnetic Compatibility, APEMC 2022, pp. 605 - 607, Institute of Electrical and Electronics Engineers, Jan 2022.
The definitive version is available at https://doi.org/10.1109/APEMC53576.2022.9888525
Electrical and Computer Engineering
Keywords and Phrases
Conformal coating; Crosstalk; Electromagnetic Compatibility; Radiated emissions; Testing
International Standard Book Number (ISBN)
Article - Conference proceedings
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01 Jan 2022