A CMOS Current-Mode Full-Adder Cell for Multi Valued Logic VLSI

The thesis describes the design and implementation of a carry save adder cell for multivalued logic VLSI. A four-valued system was chosen and the logic was analyzed and minimized using the C HAMLET CAD tool [I]. SPICE was used to design and simulate the required behaviour of the current-mode CMOS circuits. A VLSI test and evaluation integrated circuit was implemented with MAGIC and fabricated through the MOSIS service. The completed IC was tested and evaluated using a specially designed binary-to multi- valued logic converter and decoder. Engineering modifications to the original current-mode inverter cells used by HAMLET were made leading to significant power savings in a complete design. The fabricated device performed as predicted by SPICE simulation. Exhaustive functional testing produced correct steady-state output signals for all cases of input loadings. Finally, we show HAMLET minimization heuristics are not efficient in the design of adder cells by comparison with an alternative modulo 4 carry save adder cell in current-mode CMOS.