| 摘要 |
PURPOSE:To suppress noise due to capacitance between lead wires within a circuit board by providing a metal plate underlying the lead wires communicating signals with circuit elements, and a dielectric plate sandwiched by the lead wires and the metal plate. CONSTITUTION:A dielectric plate 2 having size substantially equal to that of a circuit board 7 is placed under a lead wire 1 communicating signals with an LSI chip 4. A metal plate, i.e., a ground plane 3, having same size as the dielectric plate 2 is provided underlying the dielectric plate 2. The lead wire 1 and the ground plane 3 form a capacitor through the dielectric plate 2. The constitution where the dielectric plate 2 is sandwiched by the lead wire 1 and the underlying ground plane 3 provides an increased capacitance. Furthermore, noise voltage due to electrolytic coupling between lead wires can be suppressed. |
