I have a question about CPU fanout. I am a beginner in the PCB layout. I have a project which is simple (one SOC AM3358 TI + one UART interface + 1 DDR3 memory chip + one PMIC TPS65217C). That s all. I want to begin with the minimum. So now im doing the SOC fanout. In the attachement i sent you a screenshoot of the SOC BGA with GND pins highlighted. Can I connect multiple pads to a single via because otherwise it is really painful? I mean Will the SOC work if it is done this way?
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BGA FANOUT
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It is not optimal but in some cases you need to do it. The key is to try to minimize it as much as possible, since it can eventually create problems which are hard to troubleshoot.
Why do you think you can't use separate vias? What is limiting the space you have? In your cases, since you barely have any interfaces wired, you are probably doing something wrong if you need to share too many vias. Give us some more information please.
It could be very useful to you if you can check some reference designs with this SoC or find a design guide for it or for a similar one.
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I absolutely agree with mairomaster. I guess, you will need to adjust placement. Have a look at the reference design or have a look at other boards like
OpenRex.
otherwise it is really painful
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Yes, you can.
BTW: Just yesterday I had a webinar exactly about this topic: Advanced PCB Layout - CPU, Memory & BGA Power Fanout (Free)
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Originally posted by robertferanec View PostYes, you can.
BTW: Just yesterday I had a webinar exactly about this topic: Advanced PCB Layout - CPU, Memory & BGA Power Fanout (Free)
Can I have access to this webinar? Is it recorded?
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For example if i have 5 power pins in my bga and i have to connect 2 decoupling cap to these pins, do i have to connect these caps to all pins or can i just connect two pins to these 2 caps and connect the others pins to the power plane?
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