Capacitor room should not face west

Where should a capacitor and a via be placed?

Second best is to put the two vias on the same side of the cap, as close as possible to each other and the capacitor. An additional set of vias can be placed on the opposite side of the capacitor to cut the inductance in half, but make sure that the two via groups are at least a board thickness (or two plane distances) apart.

How do you put a decoupling capacitor on a board?

(My usual layout technique is to place the load, then place the power and ground vias, and finally place a decoupling capacitor on the opposite side of the board if there's room. (If there's no room, the capacitor moves, not the vias!)

Can traces be shared with decoupling capacitors?

These vias can be shared with decoupling capacitors, but it is better to have more plane vias than to lengthen traces to plane vias. (My usual layout technique is to place the load, then place the power and ground vias, and finally place a decoupling capacitor on the opposite side of the board if there's room.

How do you fill a capacitor with a via?

Putting the via in the pad is the best option, if you can afford it (you need to fill the via and plate the pad over the fill, which adds a day or two to fabrication and costs more money). Second best is to put the two vias on the same side of the cap, as close as possible to each other and the capacitor.

How do you place a decoupling capacitor in a FPGA?

General Rules for Capacitor and Power Plane Placement Place each decoupling capacitor in close proximity to the corresponding power plane it decouples, so the capacitor mounting inductance loop is minimized . If possible, place the power and ground planes in close proximity to the FPGA device so they minimize the BGA via inductance loop.

What is the function of a bypass capacitor?

Bypass capacitors serve four primary functions: Diagram (A) in Fake Name's answer is by far the best one for minimizing changes drawn on the supply wires, since changes in the current drawn by the CPU will have to change the cap voltage before they can cause any change in the supply current.