Correct PCB pad design, if there is a small amount of skew during patch processing, can be corrected during reflow welding due to the action of surface tension of the molten solder.
Through the above analysis of the parasitic characteristics of the holes, we can see that in high-speed PCB design, seemingly simple holes often bring great negative effects to the circuit design.
In the design of high density PCB, the use of non-through-hole and the reduction of through-hole size also bring the cost increase, and the through-hole size can not be reduced indefinitely, it is limited by PCB manufacturers drilling and electroplating t
When the power supply or ground short circuit is found during debugging, the zero ohm resistance can be removed to narrow the search range.
Many PCB manufacturers have to go through the network connection test of power-on before PCB processing is completed, to ensure that all the connections are correct.
This top view provides an example of installing a row of ground through holes in the top metal ground area on each side of the intermediate conductor. The circuit current caused by the top layer is short-circuited to the ground below.
The problem is clear. A technically correct but confusing schematic is still a bad schematic." Although this view is easy to accept, in CAD programs, an unreadable schematic diagram can still describe the circuit connection information, and is still ...
Therefore, welding resistance data cannot be generated directly from similar pad. When applying solder resistance, the filler block area will be covered by solder resistance, resulting in difficulty in welding components.
Similarly, there is also a parasitic inductance through the hole. In high-speed digital PCB, the harm caused by the parasitic inductance is often greater than the parasitic capacitance.
What is the core power supply, is some power supply current, the number of the kind. A plane, not more than 3 power supply division. It is important to consider that segmentation cannot present current-carrying bottlenecks.
At the same time, it should be noted that the transmission line on the PCB should not have mutations or corners, and the impedance of each point of the transmission line should be kept continuous as far as possible, otherwise there will be reflections bet
Therefore, the relationship between the hole and the pin inductive reactance must be considered and the priority of the pass hole specification must be set.
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