LVDS issues … exactly the same lenght / impedance on all I/O lines and add common mode chokes on all lines aswell.
Best regards Amund Fra: alfred1520list [mailto:[email protected]] Sendt: 15. oktober 2016 07:41 Til: [email protected] Emne: Re: [PSES] RE from Flat Panel ICs Hi Eugene, Jokes aside, may be the meaning of general recommendations have different meanings to us so let's clarify that and see if it takes us any closer to finding help for you. By focusing on chips specific causes to the RE problem implies that you have ruled out all other causes of the RE problems. One way to draw such conclusion is having a number of different designs differing only in the LVDS drivers chip being used. All other aspects such as circuit design, PCB layouts, peripheral connections, enclosures, environments, etc. are all significantly the same or identical. Thus the only variable is the LVDS drivers. Only then could we be blaming the chip and looking for chip specific causes. Otherwise you may risk chasing the wrong tail. It's worth stating my favorite statement about debugging: if one made the wrong assumption, one may never find the problem, so when you are facing a dead end, re-examine your assumptions. The most famous example is the software bug that causes the computer not to boot is an unplugged power cord:) I apologize if I am merely repeating everything you already know very well. Again, wrong assumption leads to dead end and that helps nobody. Best of luck debugging. Sincerely Alfred On October 14, 2016 3:17:26 PM PDT, John Woodgate <[email protected] <mailto:[email protected]> > wrote: The ICs themselves are too small to produce significant RE. The RE comes from the PCB tracks and external cables. But of course you know that. With best wishes DESIGN IT IN! OOO – Own Opinions Only <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England Sylvae in aeternum manent. From: MARINA PEYZNER [mailto:[email protected]] Sent: Friday, October 14, 2016 10:25 PM To: [email protected] <mailto:[email protected]> Subject: Re: [PSES] RE from Flat Panel ICs Actually, my question was about Flat panel driver ICs, particularly about chips Intersil Techwell TW8804 and National Semiconductor DS90C385A. I had hope that somebody has valuable experience with this problem. Thank you anyway, Eugene On Friday, October 14, 2016 2:12 PM, alfred1520list <[email protected] <mailto:[email protected]> > wrote: And general recommendation! s also say to reduce common mode current. But obviously this shouldn't have been said too:) On October 14, 2016 9:24:36 AM PDT, John Woodgate <[email protected] <mailto:[email protected]> > wrote: It seems to me that claiming familiarity with general recommendations severely restricts what anyone can add. The general recomm! endation for reducing RE is to minimise the areas of current loops by pairing 'go' and 'return' conductors on adjacent layers of the PC board. But you obviously know that already. With best wishes DESIGN IT IN! OOO – Own Opinions Only <http://www.jmwa.demon.co.uk/> www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England Sylvae in aeternum manent. From: MARINA PEYZNER [mailto:[email protected]] Sent: Friday, October 14, 2016 5:08 PM To: [email protected] <mailto:[email protected]> Subject: [PSES] RE from Flat Panel ICs Dear experts, Flat panel driver ICs are known for their high emission. I have some problems with radiated emissions particularly from chips Intersil Techwell TW8804 and National Semiconductor DS90C385A. Could you, please share your knowledge about reducing this RE. We are familiar with general recommendations. Thank you, Eugene - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-p! stc 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 (in! cluding 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] <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]> > -- Sent from my Android phone with K-9 Mail. Please excuse my brevity. - ---------------------------------------------------------------- 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]>
