Paolo, My experience has been that if it is an Optical Isolation Circuit, the actual RF isolation is usually far from desirable because of undesirable capacitive coupling that occurs within the transmit and receive circuitry.
I would suggest that you determine if undesirable coupling occurs when the circuit is either active or inactive or all the time. Also, try removing the high-side of power from either side of the Isolation Circuit and determine if the undesirable RF coupling disappears. Between these two experiments, this should give you a pretty good idea of the causal relationship. Regards, Jeffrey W. Greilich EMC Technical Manager Automotive Systems Laboratory, Inc. 27200 Haggerty Road, Suite B-12 Farmington Hills, MI 48331 (248) 848-2771 (Office) -----Original Message----- From: Paolo Peruzzi [mailto:paolo.peru...@esaote.com] Sent: Monday, February 25, 2002 10:34 AM To: emc-p...@majordomo.ieee.org Subject: PCB floating area layout Hi all, I'm dealing with a PCB that has a floating section isolated from the rest of the board for safety purposes (patient applied part). I found out some problems with emissions, due to the coupling between the floating part and of the PCB and the earthed one. My questions are concerning the layout design of the floating area: 1) Is it best to minimize the HF capacitive coupling between the earthed ground and the floating ground or to maximize it? 2) Is it best to reduce the amount of the floating ground or to increase it? Does it depend on the goodness of the "main ground", i.e. how much it is "cold" ? (I see the board as a dipole with one end connected to earth, and the other floating). Thanks, p.p. ------------------------------------------------------------- ESAOTE S.p.A. Paolo Peruzzi Research & Product Development Design Quality Control Via di Caciolle,15 tel:+39.055.4229306 I- 50127 Florence fax:+39.055.4223305 e-mail: paolo.peru...@esaote.com ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
