A simple and accurate capacitance ratio measurement technique for integrated circuit capacitor arrays

The key performance of many analogue circuits is directly dependent on precise capacitance ratios. To perform an accurate characterization of nonunity capacitor ratios, a floating-gate AC nulling technique is proposed. A test-structure containing the floating-gate and a binary-weighted capacitor array has been designed, fabricated and tested in the AMIS C035 process. The technique is proven to be accurate, robust and easy to use.