Susceptibility of CMOS Voltage Comparators to Radio Frequency Interference

This paper deals with the susceptibility to radio frequency interference of common CMOS voltage comparators. Approximate nonlinear analysis and time domain computer simulations are carried out to highlight the causes of the false commutations induced by the disturbances superimposed onto the nominal input signals. Through these investigations it is shown that the response of voltage comparators to radio frequency interference depends on the comparator initial state. This effect is also confirmed by the results of measurements carried out on a CMOS voltage comparator embedded in a test chip. Based on this, a new voltage comparator that avoids false commutations induced by high frequency disturbances is proposed.