| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a printed wiring board which well removes the high frequency noise components of a power voltage and suppresses newly generated unwanted radiation noises low to greatly reduce the noise on the whole. SOLUTION: The printed wiring board is composed of a first signal layer 12, a GND layer 14, a power source layer 16a and a second signal layer 18a. Capacitors 36 grounded to the GND layer 14 and power wirings 22a-22g extending up to the top layer of a sub-power source layer 28a are connected to a first pad 20a to a ninth pad 20i. Vias 25a-25g piercing the GND layer 14 to connect with the sub-power source layer 28a are connected to the power wirings 22a-22g. The sub-power source layer 28a is provided on the same layer as the main power source layer 26a, located at a specified position in an approximately elliptic opening 34a of the main power source layer 26a in approximately an elliptic shape so as not to directly connect to the main power source layer 26a, and fed with a power voltage from the main power source layer 26a through an L-type filter 40.</p> |
