Abstract: A metal insulated semiconductor field effect transistor (MIS-FET) includes a substrate, a semiconductor layer, and an oxide film on the semiconductor layer. Source and drain regions are formed by doping the semiconductor layer with impurities. A gate electrode is formed on the oxide film between the source and drain regions. An electrode is provided on the opposite side of the drain region from the gate electrode without contacting the gate electrode. The electrode is connected to either the source region or the substrate. Thus, a high strength against static electricity is performed without using a large area on the chip.

Abstract: A muting control circuit is provided in which muting is performed when any one of a plurality of unlock detection signals is detected, indicating circuits is unlocked or when a data error is detected in a demodulator. In this way, reading time can be shortened to the minimum time required for muting. In addition, when one unlock detection circuit is triggered due to a disorder in the input, the unlock detection signal is provided immediately, so that the muting control signal is supplied and muting can be performed even when there is a time delay before the unlock detection circuit detects an unlocked state.