Design of novel multiplexer based thermometer to binary code encoder for 4 bit flash ADC

Abstract

In this paper, a novel multiplexer based thermometer to binary Code Encoder For 4 Bit Flash ADC is proposed. The proposed encoder design uses 2:1 multiplexes (MUX) and 2 input XOR gates for converting thermometer code to binary code. Initially 2:1 MUX are used to convert the thermometer code to equivalent gray code. The resulting gray code is then converted to the binary code using XOR gates. Low power consumption is achieved in the proposed design with the grounding concept and avoiding the additional inverters compared to the conventional encoder design. The proposed encoder is implemented in 180 nm CMOS, N-well technology with 1.8 V supply voltage and was simulated using Cadence Spectre simulator. Simulation results shows reduction in power up to 60% when compared with conventional encoder architectures. The proposed design has a figure-of-merit (FOM) of 13.28 fJ with the propagation delay of 0.5180 ns.