Rules of thumb can be very dangerous things. Steve. On 12/28/2012 10:40 AM, Lynne C. Green wrote: > I seem to remember another rule of thumb about keeping digital and > analog grounds separate all the way to the edge of the PCB. Ditto power > if possible. > > - Lynne > > > On 12/28/2012 2:15 AM, Elya B. Joffe wrote: >> Dear all, >> I would suggest that the "frequency" above which to use Multi-Point >> grounding should be determined not only by "clock rate" (i.e., PRF) but >> primarily, by edge rate. Since edge rates all today mostly in the >> sub-nanosecond, I would suggest that for digital circuits, multi-point >> would probably be the best strategy. >> >> In case of doubt, I use a single "hard" connection and multiple >> capacitive-coupled ground connections (frequency-selective grounds). >> This would offer multi-point connection at higher frequencies and >> single point at lower frequency. >> >> Happy New Year, >> >> Elya >> >> On 28/12/2012 10:53, Tesla wrote: >>> Hi, >>> >>> Happy holiday. >>> Read a app note written by Intel--Intel IXP42 product line of network >>> processor and IXC1100 control plane processor. For the grounding issue,Page >>> 65, it use follow guideline: >>> >>> Use single-point grounding for low-frequency applications (audio, etc.) >>> with clock rates of 1MHz or lower. >>> Use multi-point grounding for high-frequency circuits with clock rates of >>> 1MHz or higher. >>> I know single-point is a tech used when in these days multi-layer PCB is >>> not popular. For two layer PCB,it is a good design thumb rule. >>> Do we still need use single-point grounding for low frequency audio signal >>> with complete ground plane PCB in today? >>> >>> Regards. >>> >>> Tesla. >>> >>> ------------------------------------------------------------------ >>> To unsubscribe from si-list: >>> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field >>> >>> or to administer your membership from a web page, go to: >>> //www.freelists.org/webpage/si-list >>> >>> For help: >>> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field >>> >>> >>> List forum is accessible at: >>> http://tech.groups.yahoo.com/group/si-list >>> >>> List archives are viewable at: >>> //www.freelists.org/archives/si-list >>> >>> Old (prior to June 6, 2001) list archives are viewable at: >>> http://www.qsl.net/wb6tpu >>> >>> >>> > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > > List forum is accessible at: > http://tech.groups.yahoo.com/group/si-list > > List archives are viewable at: > //www.freelists.org/archives/si-list > > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > > > -- Steve Weir IPBLOX, LLC 150 N. Center St. #211 Reno, NV 89501 www.ipblox.com (775) 299-4236 Business (866) 675-4630 Toll-free (707) 780-1951 Fax All contents Copyright (c)2012 IPBLOX, LLC. All Rights Reserved. This e-mail may contain confidential material. If you are not the intended recipient, please destroy all records and notify the sender. ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List forum is accessible at: http://tech.groups.yahoo.com/group/si-list List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu