Mixed analog-digital circuit for linear-time programmable sorting

The paper describes a VLSI circuit for sorting analog quantities. The circuit yields analog representations of sorted values and digitally encodes the corresponding ranks in the list. The length of the sorted list can be digitally programmed at run time, hence partial sortings are also supported. The modular, mixed analog/digital structure is arranged into elementary cells operating at the local level. This greatly facilitates the layout design. A suitable coupling of current-mode and voltage-mode signals minimizes the number of transistors.