ABSTRACT
Testing of electronic circuits is an active research topic in recent years [1-6] and it remains crucial, especially for the rapidly developed mixed-mode (analog and digital) circuits. This is mainly due to the difficulties inherent to the nature of analog signals. The conventional fault models [6] for analog circuits are the catastrophic or hard faults, where an analog component becomes open or shorted and the parametric faults, where the value of a component such as R, L, C, or the value of a transistor parameter (transconductance, Vth, etc.) changes sufficiently outside the tolerance limits and causes unacceptable circuit performance. Process imperfections [6] due to subwavelength lithography, etching, and variation of the number of dopants in the channel of short channel devices result in large variations of related circuit parameters and particularly of the threshold voltage (Vth). Statistical variations in device parameters lead to a statistical distribution of Vth.
