Chapter 21
Checkers for Online Self-Testing of Analog Circuits
21.1 Introduction
Testing of integrated circuits (ICs) refers to the procedure of verifying the compliance of their performances to specifications after manufacturing. This procedure is applied to rule out the possibility that an IC is defective and, thereby, to ensure the correct operation of the entire system wherein it is deployed. Defects are likely to occur since each manufacturing step is subject to imperfections. The origin of the defects may vary and may not be always well understood. The net result could be short- or open-circuits, missing, under-etched or misaligned vias, doping errors, nonuniformly distributed oxide thicknesses across the wafer, mismatch, parasitic capacitances, broken bond wires, etc. A defect could lead to complete malfunctioning of the IC or to variations in its performance.
Even when an IC passes successfully the manufacturing testing step, it might fail in the field during its normal operation. This could be due to electromagnetic interference, particle strikes in radiation intense environments, crosstalk, heat dissipation, thermal cycling, negative bias temperature instability (NBTI), hot carrier injection (HCI), time-dependent dielectric breakdown (TDDB), etc. These phenomena are becoming more prominent as ...
