| 摘要 |
<p>A multi-chip module (3) is constituted by mounting high-speed operation circuits, such as a data processor bear chip (11) and memory bear chips (12a to 12d), constituting an electronic circuit (1) on a multilayer wiring board (10). The multi-chip module (3) is mounted on a wiring board (2) constituting an electronic circuit (1). In such a multi-chip module, buffer circuits (13a to 13e, 14) are inserted in an in-module bus for common connection between the data processor and memory chips. The buffer circuits are data input/output buffers which are brought into high-impedance states in response to selection of operation of an address output buffer, a control signal output buffer, and the memory chip. Even though the resistance to high-frequency noise is enhanced by the use of the multilayer wiring board, external noise tends to enter the memory through the in-module bus interconnecting the data processor chip and the memory chip when the data processor chip makes an access to the memory chip. However, the buffer circuits block entry of such external noise and prevent the memory data from being destroyed because of high-frequency noise during the memory access.</p> |
