A comparator is provided that compares one or more input signals in a regenerative circuit. One or more switched isolate the signal inputs after regeneration has started but before regeneration has reached such an extent that large voltage swings in the regeneration circuit are transmitted back to the signal source and corrupt the signal source or neighboring circuits. Furthermore, as controlled by a control circuit, the instant of isolating the signal source can be dependent on the degree of regeneration such as being dependent on a predetermined degree of regeneration. The comparator may be incorporated in an electronic device such as an analog-to-digital converter or a wireless receiver or transceiver.