High-speed high-precision CMOS analog rank order filter with O(n) complexity

A continuous-time implementation of a voltage-mode analog rank order filter is presented. The proposed circuit features high speed, high precision, and simple circuit implementation. The overall architecture exhibits linear increase of complexity with the number of inputs (O(n)), at the rate of seven transistors per input. Rank is easily programmable with the tail current for all rank order values from the Max to the Min case, and the programmed function is accurate for a wide range of tail currents. Moreover, unlike previously reported rank order structures the precision of the proposed circuit does not rely on perfect matching of all input transistors. Simulations as well as experimental results are presented that verify the functionality and performance of the proposed circuit.