| ??? 03/09/06 13:53 Read: times |
#111706 - Splitting the ground plane Responding to: ???'s previous message |
Russell said:
Why would you want to separate the analog and digital grounds when you should have a solid groundplane? The reason behind separating them is to get around the problem of a non-ideal groundplane and/or ground wiring. In mixed systems, where you need very high precision, a single solid ground plane is not fully satisfying. It can short circut ground noise, but only to some extent. When very high precision is needed a splitting of ground plane is essential. Russell said:
Say you have your two ground planes - analog and digital - how do you join them? With a large track? Under the AD9835. At a point, not via a track. Russell said:
This becomes,in effect, a solid groundplane with the smallest inductance and resistance. Got to be good for EMC. Of course, but not good for high precision. Russell said:
In the latest mobile phones, I can't see separate groundplanes - they all look like the one and the same. Do they have high precision analog processing in it, 16bit ADCs, or similar? Do they specify distortion factor of signals? Russell said:
They do segregate areas with tracks on the outer layers and put tin cans over critical areas. Why using tin cans, when a splitting of ground plane is enough? Russell said:
So is this separate ground plane concept a thing of the past with multilayer boards? Not at all. Have a talk with manufacturers of high precision ADCs/DACs... Kai |
| Topic | Author | Date |
| AD9835 noise problem | 01/01/70 00:00 | |
| noise | 01/01/70 00:00 | |
| Recommendations | 01/01/70 00:00 | |
| quick fix? | 01/01/70 00:00 | |
| Maybe | 01/01/70 00:00 | |
| Transmission lines | 01/01/70 00:00 | |
| 5MHz? | 01/01/70 00:00 | |
| Spectrum analyser | 01/01/70 00:00 | |
| It's ground noise | 01/01/70 00:00 | |
| ground noise and groundhogs | 01/01/70 00:00 | |
| Harmonics as well | 01/01/70 00:00 | |
| comments | 01/01/70 00:00 | |
| Why separate the analog & digital gnds? | 01/01/70 00:00 | |
| Splitting the ground plane | 01/01/70 00:00 | |
| Evaluation board | 01/01/70 00:00 | |
| thin ground? | 01/01/70 00:00 | |
| that is why you use star | 01/01/70 00:00 | |
| Ground wire in parallel | 01/01/70 00:00 | |
| and a twisted pair? | 01/01/70 00:00 | |
| Would do! | 01/01/70 00:00 | |
| does not exist, Jan if you used twisted | 01/01/70 00:00 | |
| The clock signal? | 01/01/70 00:00 | |
| oh well | 01/01/70 00:00 | |
| Indeed | 01/01/70 00:00 | |
| is there a way... | 01/01/70 00:00 | |
| Hardly | 01/01/70 00:00 | |
| unfortunately not | 01/01/70 00:00 | |
| twisted pair | 01/01/70 00:00 | |
| is that not obvious | 01/01/70 00:00 | |
| No ground traces, but patches | 01/01/70 00:00 | |
| the bane of many | 01/01/70 00:00 | |
| Why 1 or 2 layers | 01/01/70 00:00 | |
| it's nice! | 01/01/70 00:00 | |
| No Secrets | 01/01/70 00:00 | |
| DALO 2M professional | 01/01/70 00:00 | |
| UV ink Problem | 01/01/70 00:00 | |
| Mixed method? | 01/01/70 00:00 | |
| No Need for DALO | 01/01/70 00:00 | |
| CE | 01/01/70 00:00 | |
| Single step mode | 01/01/70 00:00 | |
| If you want... | 01/01/70 00:00 | |
| mmm | 01/01/70 00:00 | |
| Dreaming | 01/01/70 00:00 | |
| LAYOUT | 01/01/70 00:00 | |
| 100nF caps | 01/01/70 00:00 | |
| 100nF ? | 01/01/70 00:00 | |
| ok | 01/01/70 00:00 | |
| Some checks | 01/01/70 00:00 | |
| It's my daily job! | 01/01/70 00:00 | |
| Unfortunately, no | 01/01/70 00:00 | |
| simulate double-layer | 01/01/70 00:00 | |
| Seperate Analog and Digital Supply | 01/01/70 00:00 | |
| RLC-filters don't help? | 01/01/70 00:00 | |
| separate | 01/01/70 00:00 | |
| And... | 01/01/70 00:00 | |
| Seperate Supplies | 01/01/70 00:00 | |
| Evaluation board | 01/01/70 00:00 | |
| No not that one... | 01/01/70 00:00 | |
| Curly | 01/01/70 00:00 | |
| OT: Hair | 01/01/70 00:00 | |
| lets have pictures | 01/01/70 00:00 | |
| No no... | 01/01/70 00:00 | |
| http://www.k6ese.com/Mar_Vista_Shack.htm | 01/01/70 00:00 | |
| but it is relevant | 01/01/70 00:00 | |
| No wonder... | 01/01/70 00:00 | |
| waveforms | 01/01/70 00:00 | |
| Link to DDS page | 01/01/70 00:00 | |
| Add the second stage... | 01/01/70 00:00 | |
| Filter components | 01/01/70 00:00 | |
| clock | 01/01/70 00:00 | |
| What clock | 01/01/70 00:00 | |
| ? | 01/01/70 00:00 | |
| Sampling theorem | 01/01/70 00:00 | |
| But... | 01/01/70 00:00 | |
| Can't find it now | 01/01/70 00:00 | |
| Ground of probe? | 01/01/70 00:00 | |
| even better | 01/01/70 00:00 | |
| Good trick! | 01/01/70 00:00 | |
| same point | 01/01/70 00:00 | |
| Both | 01/01/70 00:00 | |
| I feel strong now! | 01/01/70 00:00 | |
| Funny! | 01/01/70 00:00 | |
| Depends... | 01/01/70 00:00 | |
| Oh Dear | 01/01/70 00:00 | |
| NO analog outputs | 01/01/70 00:00 | |
| since there is no schematics presented | 01/01/70 00:00 | |
| Publishing failed | 01/01/70 00:00 | |
| then give a link to an ORCAD drawing | 01/01/70 00:00 | |
| Schematics | 01/01/70 00:00 | |
| corrections | 01/01/70 00:00 | |
| Big test | 01/01/70 00:00 | |
| Try This Schematic... | 01/01/70 00:00 | |
| one more problem | 01/01/70 00:00 | |
| I miss the second 300R resistor | 01/01/70 00:00 | |
| Terminating Resistor. | 01/01/70 00:00 | |
| Answers | 01/01/70 00:00 | |
| University of Kai | 01/01/70 00:00 | |
| Keep us informed... | 01/01/70 00:00 | |
| of course | 01/01/70 00:00 | |
| Update | 01/01/70 00:00 | |
| Eager to know | 01/01/70 00:00 | |
| Me too | 01/01/70 00:00 | |
| Autoreload | 01/01/70 00:00 | |
| Current source output | 01/01/70 00:00 | |
| Electronic World Feb 06 | 01/01/70 00:00 | |
| Superb! | 01/01/70 00:00 | |
| No surprise | 01/01/70 00:00 | |
| AD9835 Cycles | 01/01/70 00:00 | |
| Solid Ground Plane Update!!!!! | 01/01/70 00:00 | |
| Very nice results! | 01/01/70 00:00 | |
| Low frequency | 01/01/70 00:00 | |
| SLIGHt correction | 01/01/70 00:00 | |
| OPA27? | 01/01/70 00:00 | |
| Cross talk on PCB tracks | 01/01/70 00:00 | |
| Have a look at this plot | 01/01/70 00:00 | |
| Interesting question | 01/01/70 00:00 | |
further interesting question | 01/01/70 00:00 |