Design and Studies of C/V Circuit for Small Capacitance Measurement
Zongguang Yu · 2010
Based on the principle of charge amplifier,a high performance operational amplifier was designed to shield stray capacitance,which enables high reliability small capacitance measurement.Fabricated in CSMC's 0.5 μm CMOS process and simulated with Cadence Spectre,the circuit can measure small capacitance precisely with a resolution of aF.Finally,mismatch of differential nominal capacitance caused by inevitable manufacturing errors was analyzed and calibrated.Results showed that mismatch only led to fixed drift,but no significant effect on sensitivity of the C/V circuit.