Low-noise dynamic comparator circuit with selectable input-referred thermal noise voltage

A new method for reducing input-referred thermal noise of dynamic comparator circuit without increasing load capacitance as commonly used in the conventional method is proposed. An implementation circuit with selectable low-noise mode operation is presented, which enable both low-noise mode and standard mode operation by a single circuit. Simulation in 180 nm CMOS process technology shows that the proposed new method and circuit topology can achieve up to 90% increase in gain of comparator first stage, resulting in up to 40% decrease in input-referred thermal noise voltage, compared with a conventional circuit with similar load capacitance. The proposed circuit is also able to operate with similar performance as the conventional circuit when low-noise mode operation is not necessary.