| 摘要 |
PROBLEM TO BE SOLVED: To finely adjust bias voltage under control from the outside, even after packaging without increasing the chip area so much. SOLUTION: This circuit has a transistor FET1 for signal-processing and a bias-adjusting circuit 1, which adjusts its bias voltage. The bias-adjusting circuit 1 has control terminals Tc0 to Tc2, a 1st terminal Tgg and a 2nd terminal Tss, to at least one of which a specific voltage is applied, and switching elements Tr0 to Tr2, which are connected between those 1st and 2nd terminals and are turned on and off according to logic signals V0 to V2 applied to a plurality of control terminals, to vary the resistance value between the 1st and 2nd terminals. The switching terminals Tr0 and Tr2 may be connected in series or in parallel. Some of resistances R0 to R2 may be connected in parallel with the series-connected switching elements or in series with the parallel- connected switching elements.
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