PURPOSE: To enable the minute setting of a comparison level and thereby to enable the reduction of nonuniformity of the comparison level and the increase of a packaging density, by a method wherein the output side of a first inverter is fed back to the input side thereof to make it operate as a buffer amplifier.

CONSTITUTION: A device is constituted by a first inverter 2 constructed of CMOS and a second inverter 3 constructed also of CMOS, and it receives an input signal through a capacitor 4 for input and a resistor 5. The inverter 2 has a resistor 6 for feeding back the output side to the input side and so operates as a buffer amplifier, a threshold value of which is determined by the ratio in the number of elements or in gate areas between P-channel transistors Trp and N-channel transistors Trn or between transistors in connections reverse thereto. By constituting the device by the two inverters 2 and 3 having different threshold values as stated above, a comparison level can be set on the basis of the difference between these threshold values. As the result, the comparison level of a comparator can be set minutely without using a large number of resistors.