Help needed on PCB Multi-Layer Order/Position

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#1
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Hi there,

I am currently making a 6-layer PCB (top, bottom, 4 layers inside). The 4 layers inside the PCB are:

1. Digital Ground (for logic, AVR)
2. Analog Ground (for sensors, A/D ex)
3. 3.3V
4. 3V

I would like to know , in which order should these 4 layers be for lowest noise performance.

Any help would be appreciated.

Thanks
Jacques

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I'd put the digital ground and 3.3V layers on the inside as they will be carrying the fast high-current stuff, and you will get the maximum inter-layer capacitance that way. You can probably get away with four layers if you are careful, they'd be a lot cheaper.

Leon

Leon Heller G1HSM

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If you can locate your components so the analog parts are all in one part of the PCB, you could probably strip off two layers and have the following buildup :
top: tracks
inner1: gnd
inner2: 3.3 and 3V
bot: tracks.

The inner layers would have separate areas for the analog GND with a single bridge between Digital GND and Analog GND.
Same with power layer,

/Jesper
http://www.yampp.com
The quick black AVR jumped over the lazy PIC.
What boots up, must come down.