A frequency model of a continuously driven clocked CMOS comparator with the effect of the input signal during regeneration is presented. The model utilizes a small-signal linear model derived from the theoretical analysis of the comparison error caused by the transition from the tracking mode to the regeneration mode. The comparison error voltage is a function of input signal frequency and is represented with the transfer function. The correctness of the model is assured by several transistor-level simulation results. The model provides a valuable insight for the design of high-speed comparators.