Rene Harder wrote: > > ECN0038: 39pF+18pF ~= 56 pF ? > You found it! ;-)
Just because I had 38+18 = 47 in my own notes as well ;-) > Do you mean the EMI protection of the headset jack! Sure using an > integrated filter works with me, I just thought we do not want too many > new components. Yes. Ideally, I would use a "general-purpose" EMI filter, such as the Murata NFL18ST series. http://search.murata.co.jp/Ceramy/image/img/PDF/ENG/L0112S0119NFL18ST.pdf They're 0603, and the data sheet promises truly magic characteristics, including zero insertion loss at DC. The downside is that it seems only Murata makes such things. Also the Rohm MCF18 series, particularly the MCF182CN102 may be suitable (and is a lot cheaper): http://www.rohm.com/products/databook/emi/pdf/mcf18.pdf Fun things I found along the way: a one-stop shopping EMI and ESD solution for USB: http://www.st.com/stonline/products/literature/ds/10950/emif02-usb01f2.pdf The same for SDIO: http://www.st.com/stonline/books/pdf/docs/13195.pdf > However, I think discrete filter are more flexible regarding vendor or > parameter changes. What I'm not sure about is what parameters we really need. Most of the signals we want to filter are slow: < 20 kHz for audio, < 1 MHz for UART, < 4 MHz for SIM, <= 25 MHz for SDIO. The big interferences are all in the GHz range. So a filter with a cut-off frequency around 100-300 MHz ought to be okay, right ? - Werner _______________________________________________ gta02-core mailing list [email protected] https://lists.openmoko.org/mailman/listinfo/gta02-core
