Multi-layer substrate module and wireless terminal device

Abstract

In a multi-layer substrate module receiving from an external earth node ( 20 ) supply of a reference potential (Vss) for grounding, a plurality of ground lines ( 170 - 1, 170 - 2, 170 - 3 ) are provided respectively corresponding to a plurality of internal circuits ( 210, 220, 230 ). Moreover, a common node (Ncmn) for coupling the ground lines ( 170 - 1, 170 - 2, 170 - 3 ) is provided in an insulating layer ( 105 C) of the multi-layer substrate module. The common node (Ncmn) is electrically coupled to the earth node 20 through a ground pin terminal 204 shared by the plurality of internal circuits ( 210, 220, 230 ). Preferably, the common node (Ncmn) is provided in the lowest insulating layer of the multi-layer substrate module. Thus, parasitic inductance of the portion through which an earth current flows, that is, the portion common to the plurality of internal circuits ( 210, 220, 230 ), can be suppressed with a small number of ground pin terminals. Accordingly, the inflow phenomenon of the earth current between the plurality of internal circuits ( 210, 220, 230 ) is prevented, enabling stable operation.

1 - 19 . (canceled)  
     
     
         20 . A multi-layer substrate module receiving supply of a reference potential from an external potential node, comprising: 
 a plurality of insulating layers laminated to each other;    at least one reference potential transmission node electrically coupled to said external potential node;    a plurality of internal circuits each including at least one circuit element formed either in one of said insulating layers or on a surface of said multi-layer substrate module; and    a plurality of reference potential lines provided respectively corresponding to said plurality of internal circuits, for transmitting said reference potential, wherein    said multi-layer substrate module is mounted on a main board, said multi-layer substrate module further comprising:    a plurality of signal transmission nodes each for receiving and outputting an electric signal to and from said main board; and    a metal coating film formed so as to cover an outer surface of said multi-layer substrate module, and electrically coupled to said external potential node, wherein    each of said reference potential lines is electrically coupled to said metal coating film, and    said metal coating film is formed without contacting said plurality of signal transmission nodes.    
     
     
         21 . The thin film magnetic memory device according to  claim 20 , wherein 
 each of said reference potential lines is extended in a horizontal direction by using a single layer of said insulating layers.