Eagle 4-layer Setup

Discussion in 'General Electronics Chat' started by jwilk13, Jul 13, 2012.

  1. jwilk13

    Thread Starter Member

    Jun 15, 2011
    Hi all,

    I'm currently working on a setup for a 4-layer PCB in Eagle, and I sorta understand how to do the setup. However, I am still confused on a couple of things. My layers go as follows:

    1: Signal
    2: GND
    15: +5VDC
    16: Signal

    I'm going to be placing components on both the top and bottom layers, so I would like to be able to use vias from layer 1-2 and 1-15 as well as vias from 16-15 and 16-2. Maybe I don't understand this very well, but that's my goal (since I'll have parts on both the top and bottom that require +5V and GND).

    The best I've been able to get is using the layer setup ((1*2)+(15*16)). This creates vias from 1-2 and 15-16 as well as vias from 1-16...almost what I want.

    Does anyone have any suggestions?
  2. JMac3108

    Active Member

    Aug 16, 2010
    The normal way is to have your vias go through ALL the layers of the board.

    In Eagle (1*2+3*16) give you a 4-layer board with vias all the way through. Notice that its typical in Eagle to call the layers 1,2,3,16 rather than 1,2,15,16 which is more logical.

    Your vias will go all the way through the board and a small circle is cutout of the 5V and GND planes around each via so that it does not short to the planes.
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    Are you aware of the cost differences when using blind/buried vias?
  4. jwilk13

    Thread Starter Member

    Jun 15, 2011
    That sounds like a matter of preference, really. In my mind, it makes more sense to call them 1,2,15,16 so I know that I have the distances set between 1/2 and 15/16 pretty small. If it really matters, I'll change it. My main reasoning for not wanting the vias to go through the whole board is to conserve real estate on the top and bottom signal layers.

    I'm aware of them...in the loosest meaning of the word. I know that it's more expensive, but I would only be using blind vias if I did it the way I described it in my OP (I think). I wouldn't need vias to go between the internal layers.
  5. jwilk13

    Thread Starter Member

    Jun 15, 2011
    After starting my layout, I realize that it's probably easier to go with your guy's recommendation of just using vias that go all the way through the board. I'm going to have to (at some point) connect top to bottom for something, so it's easier to just use them that way.
  6. crutschow


    Mar 14, 2008
    For best decoupling I like to use a flooded ground plane on the active component side of the board. That way the ground pad of surface-mount caps can connect directly to the ground plane without the added resistance and inductance of a via to a buried plane.