Hi It is my understanding that the USB guidelines provide for EMI filtering at the output. That is to say: for USB1 - ferrite beads and caps, for USBII a common mode choke is recommended. Take a look in there.
Also, USB is a differential signal so appropriate design on the board needs to be considered> Best Regards Charles Grasso Senior Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Email: [email protected]; Email Alternate: [email protected] -----Original Message----- From: Darrell Locke [mailto:[email protected]] Sent: Thursday, September 19, 2002 11:15 AM To: 'Dan Pierce'; [email protected] Subject: RE: Looking for good USB EMI suppression techniques You can't do much filtering on the USB lines due to signal integrity. We have achieved good results with careful attention to PCB layout (an adequete ground plane, don't even try 2-layer) and shielding, especially with the cable. Darrell Locke Advanced Input Devices -----Original Message----- From: Dan Pierce [mailto:[email protected]] Sent: Wednesday, September 18, 2002 8:17 AM To: [email protected] Subject: Looking for good USB EMI suppression techniques Greetings: I am looking for a good design practice regarding USB transmission lines. I commonly have problems with 120.00MHz and 252.00MHz. Thanks in advance. Daniel J. Pierce Sr. Design Engineer OpenGlobe, Inc. > (An Escient Technologies Affiliate) 6325 Digital Way Indianapolis, IN 46278 mailto:[email protected] P: (317) 616.6587 F: (317) 616.6587 ------------------------------------------- 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
