| ??? 07/15/09 08:22 Read: times |
#167301 - Yes, but... Responding to: ???'s previous message |
there were 2 questions:
1) generally about the fragmented ground on the top and bottom - you answered me that it is possible so I am going to make my ground vias smaller and put them in parellel... and 2) about the switcher's ground - I have not understood it yet, sorry. There is a PCB layout in the datasheet of LM25574 - 2 layer board with gnd plane on bottom that the switcher is connected to. But I have 4 layer board and I don't know if the inner planes could be just below the switcher because of the noise. I have found somewhere on the murate website that FB could be used at the gnd and power trace so I put them into my schematic directly behind the output capacitor and that is why two separated grounds were created - ground of the switcher and common ground... I don't know what is correct and what is adequate... I am really confused ;-) I tried to draw it... A - my actual design - I thing it is not correct, but maybe yes... B, C - alternates - please, help me to choose to correct one... thank you very much...  |
| Topic | Author | Date |
| PCB design - ground plate... | 01/01/70 00:00 | |
| excuse... | 01/01/70 00:00 | |
| You can use a local ground plane, but... | 01/01/70 00:00 | |
| So, if I understand it well... | 01/01/70 00:00 | |
| Yes, of course, but... | 01/01/70 00:00 | |
| Yes, but... | 01/01/70 00:00 | |
| No overlap | 01/01/70 00:00 | |
| Version B, but without FB... | 01/01/70 00:00 | |
| so... | 01/01/70 00:00 | |
| PCB layout... | 01/01/70 00:00 | |
| Answers... | 01/01/70 00:00 | |
| EMC | 01/01/70 00:00 | |
| Hhm, I wouldn't do that... | 01/01/70 00:00 | |
| AC power supply | 01/01/70 00:00 | |
| ground vias | 01/01/70 00:00 | |
| Locating of vias... | 01/01/70 00:00 | |
| Thank you very much... | 01/01/70 00:00 | |
| Sideplating? Thermal vias? | 01/01/70 00:00 | |
| Stackup | 01/01/70 00:00 | |
| Not such a good idea | 01/01/70 00:00 | |
| interrupted/split planes | 01/01/70 00:00 | |
| Elaboration | 01/01/70 00:00 | |
| Thank you... | 01/01/70 00:00 | |
| Nice link, Rob! | 01/01/70 00:00 | |
| Elaboration | 01/01/70 00:00 | |
| Explanation | 01/01/70 00:00 | |
| Elaboration | 01/01/70 00:00 | |
| What you propose isn't well suited for 4 layer boards | 01/01/70 00:00 | |
Hi Kai | 01/01/70 00:00 |