| 摘要 |
PURPOSE:To improve the voltage reducing characteristic of a switch circuit by using a transistor formed with a base in a low impurity density active base region as a switching transistor. CONSTITUTION:A transistor which is formed of a P-type active base region 36 formed on an insular region 35 to become a collector, an N<+> type emitter region 37 formed on the region 36 and a base contact region 38 partly superposed on the region 36 is used as a switching transistor 2. Since the base is formed of the region 36, the current rising characteristic of the emitterbase junction is better than a conventional transistor, and thus the transistor has lower saturated voltage VCE (sat) when operating with a lower voltage is lower than that of the conventional one, and a potential difference used for a bias circuit is widened in the lowered amount. Thus, it can be operated to the lower power source voltage VCC by the amount in the lowered value of the VCE (sat).
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