NOISE RADIATION SUPPRESSING MEMORY MODULE

PROBLEM TO BE SOLVED: To solve the problem that, when a memory module is mounted in a device and a circuit is operated, an impedance between the ground of the device and the ground of the memory module causes a high frequency current from the circuit operation to be overlapped on the memory module ground as a noise current, with the result that the overlapped noise current flows via a connection via through a ground peripheral to a signal layer or a power supply layer, so that the module operates as a planar antenna which is made up of the ground as a ground conductor, the connection via as a power supply point, and the peripheral ground as a radiation element, and the noise is radiated from the planar antenna. SOLUTION: In a memory module using a multilayer printed circuit board including signal layers, power supply layers, and a ground layer; an ambient ground pattern provided to one of the signal layers or to one of the power supply layers and the ground layer are connected by a single via. An ambient ground pattern provided to the other of the signal layers or to the other of the power supply layers and the ground layer are connected by a single via. noise radiation from the ambient ground can be suppressed by providing the respective via positions to opposing ends of the ground layer. COPYRIGHT: (C)2006,JPO&NCIPI