High-speed PCB circuit board through-hole design

 Through the vias parasitic characteristics analysis, we can see, in the design of high speed PCB, seemingly simple through hole also tends to circuit design to bring very big negative effect. In order to reduce the parasitic effects brought adverse effect, in the design of the can as far as possible:
 1, from the cost and quality of signal two aspects into account, choose reasonable size hole size. For example, the 6-10 layer of the memory module PCB design, selection of 10 / 20Mil ( drilling / pad ) through hole is better, for some high density of small size board, can also try to use the 8 / 18Mil vias. The current technical conditions, it is very difficult to use the smaller hole. The power or ground vias may consider the use of larger size, to reduce impedance.
 2, it discusses the two formula can be derived, using a thin PCB plate is beneficial to reduce the through hole two to sendThe parasitic parameters.
 In 3, PCB board signal line as far as possible without changing the layer, that is as far as possible not to use unnecessary holes.
 4, the power and ground pins to the nearest played hole, through hole and the pin between the lead the shorter the better, because they canLeads to the increase of inductance. At the same time the power and ground leads to possible coarse, in order to reduce impedance.
 In 5, the signal change layer in the vias placed near some of the ground vias, so as to provide recent loop signal. Even in the PCB board a large number of placed some extra ground vias. Of course, when the design also needs to be flexible. The previously discussed via model is provided for each layer pad, sometimes, we can be certain layers of the pad to reduce or remove the. Especially in the through hole density is very big, may result in the copper layer to form a separate circuit fault trough, to solve this problem, in addition to move across the hole location, we can also consider the through holes in the copper layer of the pad size.