A BIST scheme for operational amplifier by checking the stable output of transient response

This paper presents a built-in self-test (BIST) scheme for operational amplifier (Op Amp). Without any parameters modification, the designed BIST system can be applied to test all the Op Amps in an analog and mixed-signal circuit, even the Op Amps are designed with different architectures. Under test mode, the Op Amp under test is converted into a voltage follower, and then as test stimulus positive and negative step signals are generated by a two-transistor transient signal generator to excite the possible defects. Finally, the stable (desired) output voltage of the voltage follower is analyzed by a voltage checker to determine the Op Amp passed or failed the test. The circuit-level simulation results of the BIST system for three Op Amps in standard CMOS 0.18-μm technology are presented to demonstrate the feasibility of the proposed BIST scheme with high fault coverage.