| 摘要 |
PROBLEM TO BE SOLVED: To provide an semiconductor device, capable of eliminating an influence of a parasitic capacity existing at a pad, even when a high-frequency signal is passed through the pad formed in a semiconductor integrated circuit and preventing an attenuation of a high-frequency signal passing through the pad. SOLUTION: A resonance circuit which becomes high impedance in a frequency of a high-frequency signal passing through a pad is constituted of a parasitic capacity and a coil 63 formed of an aluminum metal by utilizing the parasitic capacity of the pad. When the high-frequency signal is passed through the pad, an impedance is increased for the signal to suppress its attenuation. A variable capacity diode 66, having a variable capacity in response to an external voltage, is connected to the resonance circuit by taking into consideration the foot that the parasitic capacity existing at the pad is small and there are unevennesses in the parasitic capacity and the coil 63, so that its resonance frequency is variable. Thus, the resonance frequency of the resonance circuit in matching with the arbitrary frequency of the high-frequency signal which passes through the pad, to enable suppression of the attenuation with respect to the high-frequency signal passing the pad in an arbitrary frequency.
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