Noise-tolerant XOR-based conditional keeper for high fan-in dynamic circuits

A noise-tolerant XOR-based conditional keeper for high fan-in dynamic circuits is presented in this paper. Noise immunity is enhanced by conditionally turning on the conditional keepers. The conditional keeper is turned off at some critical moments to reduce the delay and power consumption. The timing of control signals and their effects on noise immunity, power and delay are also examined. High fan-in dynamic circuits are used to demonstrate the effectiveness of the conditional keeper on noise immunity. Distributed power gating combined with clock gating design is also examined. All the simulation results are based on TSMC 100 nm CMOS technology. Compared to conventional techniques, under the same unity-gain DC noise criteria, more than 20% power reduction and 20% delay reduction are achieved. Under the same delay criteria, more than 1.25× noise immunity improvement is attained.