| 摘要 |
PROBLEM TO BE SOLVED: To reduce electromagnetic-wave radiation noises emitted from a multilayer printed wiring board. SOLUTION: In the multilayer printed wiring board, a power supply layer 13 with a 5 V power-supply plane 14 and 3.3 V power-supply planes 15a, 15 are mutually installed oppositely to a ground layer (not shown) formed in a single plane shape. A wiring pattern 4b for a 5 V clock signal for transmitting a signal as an electromagnetic-wave radiation noise source is formed between the mutual 3.3 V power-supply planes 15a, 15b divided into two in the power supply layer 13. Accordingly, the current passage of a return current flowed through the ground layer is formed in a shortest straight line shape, and electromagnetic-wave radiation noises emitted from the multilayer printed wiring board can be reduced. |
