A novel active shunt-peaked MCML-based high speed four-bit Ripple-Carry adder

This paper proposes a new active shunt-peaked MOS Current Mode Logic (MCML) based four-bit Ripple-Carry adder (RCA) circuit. The technique of active shunt-peaking offer a way of enhancing the performance of MCML gates for high speed digital system designs. The technique suggests active inductor as load to RCA. The paper presents the analysis and operation of the load. The benefits of the proposed technique is verified by designing and simulating various MCML based RCA circuits using resistive, pMOS and active inductor load. An overall performance evaluation in terms of propagation delay, rise time and fall time and a comparison has been done based in PSPICE using 0.18μm CMOS technology parameters. For a power supply of 3.3 V and data rate of 2.5 GHz, the simulation results show an improvement of 11 to 36 percent in the values of delay parameters for active shunt-peaked RCA in comparison to other existing MCML loads.