| 摘要 |
PURPOSE:To obtain an integrated circuit capacity of high precision through capacity adjustment by trimming a resistance which forms a composite integrated circuit or a monolithic integrated circuit. CONSTITUTION:Resistance R1-R4 and a capacity C0 are arranged in series, shortcircuting one ends of operating amplifiers OP1, OP2 and connecting with the contact points of resistances R2 and R3. The plus terminal of OP2 is connected to the input terminal of R1 and R2 and the plus terminal of OP1 to the contact points of R4 and R5. The output of OP1 is connected to the terminals of R1 and R2 and the output of OP2 to the contact point of R3 and R4. At that time, the input impedance is represented by the formula Zin=R1R3/jomegaC0.R2R4. If this circuit is realized in the form of a thin film composite circuit, R1-R4 can easily be laser-wrought for trimming so taht the resistance value can be adjusted. If R3 and R4 are trimmed, the capacity is changed by the function of the operating amplifier, so that even if R1 and R2 were adjusted, the equivalent capacity C and be changed. In this way, it is possible to absorb the unevenness of the basic capacity C0 and at the same time, increase the precision of the capacity value upto the level of a trimming precision. |
