Process Variation-Aware Multiple-Fault Diagnosis of Thermometer-Coded Current-Steering DACs

In this brief, we first introduce a process-variation-aware test-point generation method. With this method, faults are not obscured by process variations and we are able to generate new test points by measuring a very limited number of current values on-chip and estimating values of the remaining currents. We furthermore introduce a multiple-fault diagnosis procedure where we use the process-variation aware test-point generation method. The proposed methods can also be used for structural test. For the application, we have used a thermometer coded current steering digital to analog converter, as they are widely used due to their suitability for high speed applications and the symmetric design is suitable for the application of our method. We introduce a design-for-test hardware for the diagnosis cost reduction, while implementing our methods. Experimental results show that parametric errors as small as 20% can be diagnosed with up to 97.8% accuracy