| 摘要 |
<p>PROBLEM TO BE SOLVED: To secure a return path of a charging current while suppressing the extension of the harmful oscillation in a power supply/ground under an IC due to a current through multilayer, by dividing in a high frequency mode a ground layer according to a particular ratio under an IC component or under an IC block utilizing the clearance, etc., of signal line through-holes. SOLUTION: Discontinuous parts 1 including clearances of through-holes for signal-lines provided in a ground layer 2 are ideally uniformly and sparsely arranged along a separating zone 3 around a ground 4 under an IC component. The ground 4 is separated in a high frequency mode from a whole-board ground 2 with a ratio of 3/4-1/2. Thus, a return path for a charging current can be secured while suppressing the extension, over the whole board, of the harmful oscillation in a power supply/ground under an IC component or under an IC block due to a current through multilayer.</p> |
