A squelch detector includes a first circuit, a second circuit, and a comparator. The first circuit is configured to receive a first pair of differential input signals and in response output a second pair of differential signals. The second pair of differential signals have higher voltages than the first pair of differential input signals. The second circuit is coupled to the first circuit and is configured to extract first and second voltage levels from the second pair of differential signals. The comparator is configured to output a squelch level signal based on a comparison of the first voltage level and a third voltage level. The third voltage level is based on the second voltage level and a reference voltage.