Hello Ravinder, I wasn't going to answer this as you were asking the experts ;)
Flip chips couple very well into their heatsinks compared to older wirebond packages as the silicon is much closer to the top surface. Perhaps try grounding/decoupling the heatsink or changing to a ceramic material for diagnosis of the problem? Also, the package bond inductance will probably have reduced. You could look at increasing the decoupling, especially on any digital core and driver pins. Has the manufacturer provided updated reference schematics for the new chip? Rgds James Pawson EchoStar Europe From: [email protected] [mailto:[email protected]] Sent: 23 March 2014 01:39 To: [email protected] Subject: [PSES] Higher EMI from ASIC built with new process Hi Experts, I am comparing EMI from two ASICs. Both have identical rise/fall times and signal amplitude. Yet the ASIC built with the later technology not only has significantly higher radiated emissions, but also shows much broader noise spectrum. PCB stackup and layout is identical. Please help me understand what other factors can be responsible for this anomaly. The older ASIC uses a wirebond package, whereas the new ASIC has flip chip package. Regards Ravinder Ajmani HGST, a Western Digital company 5601 Great Oaks Pkwy San Jose, CA 95119-1003 [email protected]<mailto:[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
