A substrate noise circuit for accurately testing mixed-signal ICs

A substrate coupling noise measurement technique is presented in this paper. The proposed on-chip test circuit can accurately and efficiently measure substrate coupling noise in any type of semiconductor substrate. The measured substrate coupling voltage is converted to a digital code by a simple on-chip analog-to-digital converter. The I/O pads, bounding wires, package frame, external cables, and test fixture/circuit do not affect the accuracy of the measurement. On-chip calibration is also included to further extend the test accuracy. The circuit provides an effective substrate coupling noise test technique for evaluating a variety of existing substrate coupling noise models. Less than 0.4% error as compared to SPICE is achieved.