PCB Stackup Plan and Plane Connections

[ranaya]

Hi All, few elementary questions :

I am designing a multi layer PCB in Altium using the general 6 layer stackup format as shownn below :



1. Can we connect one of the internal signal layer pcb track (or internal plane) to a though-hole component pin (let's a pin of a 2.54 mm pitch pin header) without using vias to transfer the inner routing track to top or bottom layers ?

2. And how should I define drill pairs for the intended pcb design (the standard way)? i.e. Can we use top-to-bottom via and at the same time make it connected to the internal GND plane by tying via net to GND (in away it automatically connects GND plane) ? Atleast this is possible in Altium, but if it has to be connected to GND plane, shouln't we use tpp-Gnd or Gnd-Bottom vias ?

 

[andre_luis]

1. Can we connect one of the internal signal layer pcb track (or internal plane) to a though-hole component pin (let's a pin of a 2.54 mm pitch pin header) without using vias to transfer the inner routing track to top or bottom layers ?

At first sight there should not have any impediment on doing this, but in layout everithing matters with respect to the geometry in face to the bandwidth of the signal; For instance, if accross these PTH components terminals are passing low magnitude signals, and if the terminals of these components become prone to get EMI induction (antenna effect), this should be considered for high speeds. In shorts, each application has its own constraints.

 

[ranaya]

Hi Andre, thanks for your reply. What's not clear to me is, how a connection from an internal layer/plane is made to the through-hole pin. Let's put the application aside.

Say we have a top to bottom via. And we have an internal ground plane. If we set the via net to GND, does this via automatically connect to internal ground plane as in :

 

[andre_luis]

Yes, if the via belongs to another net than GND, this net is avoided during copper pouring stage.