Structure to dampen barrel resonance of unused portion of printed circuit board via
A printed circuit board includes a first trace, a second trace, and a first via. The first trace is in a first conductive layer. The second trace is in a second conductive layer. The first via interconnects the first trace and the second trace, and communicates a first signal from the first trace to the second trace through a third conductive layer. The third conductive layer has a higher impedance than the first conductive layer and the second conductive layer.
1. A printed circuit board, comprising:
a first trace in a first conductive layer;
a second trace in a second conductive layer;
a first via to interconnect the first trace and the second trace, the first via to communicate a first signal from the first trace to the second trace through a third conductive layer plated on a wall of the first via, wherein the third conductive layer has a conductive material with a higher impedance than the first conductive layer and the second conductive layer; and
a plating layer deposited over the first trace and the third conductive layer, wherein the plating layer has a lower impedance than the conductive material of the third conductive layer.
2. The printed circuit board of claim 1 , wherein the first via is a through via.
3. The printed circuit board of claim 1 , wherein a resistivity of the third conductive layer is greater than a resistivity of the first conductive layer and of the second conductive layer.
4. The printed circuit board of claim 3 , wherein:
the first conductive layer communicates the first signal in a first conductive material; and
the first via communicates the first signal in a second conductive material.
5. The printed circuit board of claim 4 , wherein the second conductive material comprises tin.
6. The printed circuit board of claim 1 , further comprising:
a third trace;
a fourth trace; and
a second via coupling the third trace to the fourth trace, wherein:
the first via communicates the first signal in a first conductive material;
the second via communicates a second signal in a second conductive material; and
the first conductive material and the second conductive material are different types of materials.
7. An information handling system, comprising:
a processor; and
a printed circuit board coupled to the processor, the printed circuit board including:
a first trace in a first conductive layer coupled to the processor, the first conductive layer including a first conductive material to communicate a signal from the processor;
a second trace in a second conductive layer coupled to a signal load, the second conductive layer including the first conductive material;
a first via to interconnect the first trace and the second trace, the first via to communicate the signal from the first trace to the second trace through a third conductive layer plated on a wall of the first via, wherein the third conductive layer includes a second conductive material that has a higher impedance than the first conductive material; and
a plating layer deposited over the first trace and the third conductive layer, wherein the plating layer has a lower impedance than the second conductive material of the third conductive layer.
8. The information handling system of claim 7 , wherein the first via is a through via.
9. The information handling system of claim 7 , wherein the second conductive material is selected based on a resonant frequency of a stub end of the first via.
10. The information handling system of claim 7 , further comprising:
a third trace;
a fourth trace; and
a second via coupling the third trace to the fourth trace, wherein:
the first via communicates the first signal in a first conductive material;
the second via communicates a second signal in a second conductive material; and
the first conductive material and the second conductive material are different types of materials.
11. The information handling system of claim 7 , further comprising:
an equalizer circuit coupled to the first via.
12. The information handling system of claim 7 , wherein the second conductive material is tin.
13. A printed circuit board, comprising:
a first trace in a first conductive layer;
a second trace in a second conductive layer;
a first via to interconnect the first trace and the second trace, the first via to communicate a first signal from the first trace to the second trace through a third conductive layer plated on a wall of the first via, wherein the third conductive layer has a conductive material with a higher impedance than the first conductive layer and the second conductive layer; and
a plating layer deposited over the first trace and the third conductive layer, wherein the plating layer has a lower impedance than the conductive material of the third conductive layer;
wherein the first via is a through via; and
a resistivity of the third conductive layer is greater than a resistivity of the first conductive layer and of the second conductive layer.
14. The printed circuit board of claim 13 , wherein:
the first conductive layer communicates the first signal in a first conductive material; and
the first via communicates the first signal in a second conductive material.
15. The printed circuit board of claim 14 , wherein the second conductive material comprises tin.
16. The printed circuit board of claim 13 , further comprising:
a third trace;
a fourth trace; and
a second via coupling the third trace to the fourth trace, wherein:
the first via communicates the first signal in a first conductive material;
the second via communicates a second signal in a second conductive material; and
the first conductive material and the second conductive material are different types of materials.