Abstract: A semiconductor integrated circuit device is provided with, in a land formed on a semiconductor substrate, a plurality of resistor layers constituted by semiconductor layers of a conductive type reverse to that of the land, and two of the plurality of the resistor layers are connected in series between a supply voltage and a reference potential. The land of the reference potential side resistor layer of the resistor layers connected in series is formed separately from the lands of the other resistor layers, and a voltage lower than a voltage applied to the other resistor layers is applied to the reference potential side resistor layer.

Abstract: A isolation amplifier circuit comprises: an operation amplifier provided with a first and second input terminals, an output terminal, and a feedback resistor for connecting the output terminal and second input terminal; a first emitter follower, for inputting a signal, connected to the first input terminal; a second emitter follower connected between the output terminal and the feedback resistor; a third emitter follower connected between the second input terminal and a first ground impedance; and a fourth emitter follower connected between the first input terminal and a second ground impedance. In the isolation circuit, dynamic resistances of the first, second, third, and fourth emitter followers are made identical with one another.