A Time-Efficient Defect Simulation Framework for Analog and Mixed Signal (AMS) Circuits

Defect simulation time in AMS circuits is rapidly growing due to increasing circuit complexity, especially in safety-critical automotive applications which needs to meet very high defect coverage (usually >90%). Reduction in defect simulation time directly translates into reduction in overall development time. In this work, we propose a time-efficient framework to simulate various defects during pre-silicon testing of AMS circuits. The proposed method uses Verilog-A modules to realize a given defect model and tests nearly all the defects in a circuit with a single test run (for a given test condition) depending on the defect-detection scheme. To strongly validate our framework, we use two distinct defect detection schemes for operational amplifiers. The first detection scheme is the intentional offset injection (IOI) method which, predominantly, is a DC testing scheme. For this scheme, the proposed framework achieved a time-saving factor of more than 10X compared to the conventional framework. The second scheme is the oscillation test method (OTM) which is a transient testing scheme. For this OTM scheme, we show that the proposed framework can reduce the simulation time to less than 50% of the conventional simulation time. We also show that the proposed framework has no negative impact on defect coverage.