The National Semi/TI parts have been used in dozens (perhaps hundreds) of laptop and LCD monitor designs over the past 12 years or so. The video scaler suppliers are very protective of their IP, so you are likely to find the most detailed information from the LVDS driver suppliers. You should have already seen that you can only get a product brief from Intersil/Techwell, which is true for the other video scaler suppliers, most of which are in Asia.
Besides all of the helpful comments from Amund, Alfred, Brian and John, take a really good look at the designs of the LCD panels which which you are trying to interface. There are major differences in panel design with respect to grounding, power distribution, connector robustness, LVDS layout, etc. which may affect RE performance when coupled with the cable and drive electronics. The panels have been through cost reduction cycles over the years, too, which hasn't always helped with regulatory. ;-) If the TW8804 is your target scaler, it sounds like you are working w/a smaller form factor panel given its resolution range. What panel manufacturers/models are you using? Also, if you have the opportunity to look at a few physical designs (i.e. tear down some old monitors/broken laptops from a thrift store, look for tear down blogs online with photos), you'll see that shielding LVDS cables is quiet common, particularly in designs which have longer cable lengths. There is also frequently a lot of foil tape or extra sheet metal associated with grounding/shielding at the panel-end, too. Regards, Adam On Sat, Oct 15, 2016 at 2:10 AM, Amund Westin <am...@westin-emission.no> wrote: > 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:alfred1520l...@gmail.com] > *Sendt:* 15. oktober 2016 07:41 > *Til:* EMC-PSTC@LISTSERV.IEEE.ORG > *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 <jmw1...@btinternet.com> > 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 > > www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England > > > > Sylvae in aeternum manent. > > > > *From:* MARINA PEYZNER [mailto:epeyz...@sbcglobal.net > <epeyz...@sbcglobal.net>] > *Sent:* Friday, October 14, 2016 10:25 PM > *To:* EMC-PSTC@LISTSERV.IEEE.ORG > *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 < > alfred1520l...@gmail.com> 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 <jmw1...@btinternet.com> > 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 > > www.jmwa.demon.co.uk J M Woodgate and Associates Rayleigh England > > > > Sylvae in aeternum manent. > > > > *From:* MARINA PEYZNER [mailto:epeyz...@sbcglobal.net > <epeyz...@sbcglobal.net>] > *Sent:* Friday, October 14, 2016 5:08 PM > *To:* EMC-PSTC@LISTSERV.IEEE.ORG > *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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > > - > ---------------------------------------------------------------- > > 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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > > > -- > 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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > - > ---------------------------------------------------------------- > > 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 < > emc-p...@ieee.org> > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
