Fault detection of continuous time filter using nonlinear feedback based OBIST

A new Oscillation Built-In-Self-Test (OBIST) methodology is developed to reduce test time and complexity in the testing of analog circuit. The technique is incorporated to test an op-amp based filter circuit. Circuit Under Test (CUT) is converted to a robust oscillator by introducing a nonlinear feedback path during test mode. The frequency of oscillation is processed by purely digital circuit which leads high precision of testing. The proposed OBIST is validated with simulation using Cadence. The technique offers minor area overhead and high fault coverage.