Testing and Fault Diagnosis of Time-Interleaved S? Modulators Using Checksums

Mismatch of components in a time-interleaved ADC (TIADC) is a major problem which can significantly degrade the performance, even with a 0.5% mismatch. This paper describes a new technique which uses checksums for diagnosing the mismatch of components among sub-ADCs in a TIADC. In our checksum formulation, a transition matrix is used to represent the transition relationship between the current state and the next state of modulators, while another matrix is used to represent the states of a TIADCs, where the state of a sub-ADC is presented in a column vector. We have applied the checksum technique to a TIADC which contains two 1-bit fifth-order ΣΔ modulators with matched resistances and capacitances, and demonstrated that the checksums successfully detect and locate mismatches.