A circuit technique for accurately measuring coupling capacitance

A technique for accurately measuring coupling capacitance is presented in this paper. The proposed on-chip test circuit can accurately and efficiently measure the line coupling capacitance and noise voltage. A simple on-chip analog-to-digital converter converts the measured analog signal into a digital signal. The I/O pads, bounding wires, package frame, external cables, and external test circuit do not affect the accuracy of the measurement. On-chip calibration is also included to further extend the test accuracy. Less than 1% error as compared to SPICE is achieved with this circuit. The circuit provides an effective and accurate technique for evaluating a variety of existing capacitance coupling models.