DfT for full accessibility of multi-step analog to digital converters

This paper reports a Design for Testability (DfT) technique, which provides necessary diagnostic capability for signature-based and functional testing of multi-step analog to digital converters. The proposed approach permits circuit re-configuration in such a way that all sub-blocks are tested for their full input range allowing full observability and controllability of the device under test. The proposed DfT can be used for engineering pre-characterization as well, and can easily be interfaced to standards like I²C and IEEE 1149.1 TAP controllers. Experimental evidence is provided on the 12 bit multi-step analog to digital converter fabricated in standard single poly, six metal 0.09-mum CMOS.