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???
07/21/04 15:52
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#74602 - RE: How good is this Board.
Responding to: ???'s previous message
Hi Michael,
Thank you very much for your suggestions...

.(Blast that 20-40 ground/power arrangement).

I am sorry I couldn't get your point kindly put some
more light on above point.

I also agree with rerranging the capacitor location next to each crystal pin; and grounding the capacitors only to pin 20 and not to the plane (might be difficult depending on your tools.) Ground-fill under the crystal might improve emissions. If you do ground-fill, it needs to be properly anchored.

I also think my 33pf capacitor to crystal traces are somewhat longer, can you please provide me some link or layout which has smaller traces. As I have already said in reply to kai my PCB software is not allowing me to disconnect the conenction between the 33pF capacitors and GND plane I will use some other tool to modify this before I give my board for manufacturing. The new layouts posted has the crystal body grounded please let me know it's ok the way I have done it.

Also I agree that you should use 13 mil traces for all signals and use the extra space for improving power and ground.

I will modify my board for homogenous traces.

I don't know what the signals to the bottom connector are; but it can't be good to encircle the crystal with them. It'll couple noise to whatever you connect. Run them both on the same side of the crystal. And put a shield trace between the crystal signals and those I/O. If they go any distance, consider an R/C filter (47R and 0.001 uF depending on their speed).

The bottom connector is a MINI DIN 6 connector and will be used for conencting a PC type PS/2 keyboard to sytem. I can see the KBDCLK [ Keyboard Clock ] trace is encircling the crystal. In order to decouple this trace from crystal your suggestion is to put a shielding trace Do you mean a ground shield?? Still I couldn't get what do you mean by. Run them Both on the same side of the crystal.

Thanks again Mike for your suggestions.
Regards,
Prahlad Purohit





List of 22 messages in thread
TopicAuthorDate
How good is this Board.            01/01/70 00:00      
   RE: How good is this Board.            01/01/70 00:00      
      RE: How good is this Board.            01/01/70 00:00      
   RE: How good is this Board.            01/01/70 00:00      
      RE: How good is this Board.            01/01/70 00:00      
         RE: How good is this Board.            01/01/70 00:00      
            RE: How good is this Board.            01/01/70 00:00      
            RE: How good is this Board.            01/01/70 00:00      
         RE: How good is this Board.            01/01/70 00:00      
            RE: How good is this Board.            01/01/70 00:00      
      RE: How good is this Board.            01/01/70 00:00      
         Becomes better and better!            01/01/70 00:00      
            RE: Becomes better and better!            01/01/70 00:00      
               RE: Becomes better and better!            01/01/70 00:00      
   RE: How good is this Board.            01/01/70 00:00      
      RE: How good is this Board.            01/01/70 00:00      
         RE: How good is this Board.            01/01/70 00:00      
      RE: How good is this Board.            01/01/70 00:00      
   RE: How good is this Board.            01/01/70 00:00      
      To Purohit.            01/01/70 00:00      
         RE: To Purohit.            01/01/70 00:00      
   RE: How good is this Board.            01/01/70 00:00      

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