In this tutorial we are going to learn about WHAT IS VIAS IN PCB DESIGN ?
Via is part from which the connection can be taken from one layer to the other for the continuity of the
track or the connection. Vias are identical to the pins used by elements except that they can be added or
removed individually. The purpose of vias is to provide connections between different layers. Don’t use
vias for adding more elements to the layout, even if that seems easier than creating a new element. You can assign a name to a via even though you probably won’t ever want to.
1) Through hole via – A type of via that starts on an external layer & ends on an external layer –connects all the layer
2) Blind via – A type of via that starts from an external layer & ends at mid layer Example: layer 1 & 2 or last and last but one layer (called as blind bottom via).
3) Buried/embedded – A type of via that starts on a mid layer and ends on a mid layer. Example layer 4 & 5
4) Blind bottom – connects the middle layer and the bottom layer. for example in a 6 layer PCB, layer 5 & 6.
5) tented via —a via with dry film SM completely covering both its pad & its PTH. This completely insulates the via from foreign objects, thus protecting against accidental shorts, but it also renders the via unusable as a test point.
6) Dog-bone via: Its nothing but 2 Vias connected in Bone shape
7) Microvia: Blind & through vias are more frequently used with FBGA packages than buried vias. Blind vias can be more expensive as compare to through vias, but overall costs can be reduced, because signal traces can be routed under a blind via, requiring fewer PCB layers. Through vias on the other hand, don’t permit signals to be routed underneath layers, which can increase the required number of PCB layers and overall costs.
1. A trace can move to opposite sides of an individual reference plane without significant effect.
2. The effect of the first via is the greatest, but the effects of additional vias Diminish as more vias are added to the trace.