A Fault Diagnosis Technique for Flash ADC ’ s

This paper addresses the problem of diagnosis of flash ADC’s and proposes a fault diagnosis technique which employs the Differential NonLinearity (DNL) test data for fault location and identification of the analog components in the converter. In the flash ADC, a fault causes deviation of DNL data from the ideal one. Hence, DNL data can be considered as a functional signature of the ADC. This property is employed for fault diagnosis. DNL patterns are used for fault location, and DNL data are used to calculate the fault values. Both single fault cases and multiple fault cases are considered. The technique proposed here relies only on DNL test data and not on the test method, thus the diagnosis can he carried out using at-operatingspeed test data. This paper describes the concept and the detailed diagnosis algorithm. Experiments have been carried out to verify the practicality of the technique. They are presented and discussed in detail. The limitations and practical implementation issues relating to the technique are also addressed.