Oscillation-based Built-In Self Test of integrated active analog filters

A new strategy for Oscillation-based Built-In Self Test (OBIST) of active analog filters, applicable for either a whole chip or a part of complex analog and mixed-signal systems, is described. In the test mode, a Circuit Under Test (CUT) is transformed to an oscillator, and the oscillation frequency is then compared to a reference frequency. In our approach, the reference frequency is given by the Schmitt trigger oscillator, which has been realized on-chip to compensate technology variations.