An apparatus comprising a first comparator circuit, a second comparator circuit, a third comparator circuit, and a difference circuit. The first comparator circuit may be configured to generate a first intermediate current in response to a first input voltage and a second input voltage. The second comparator circuit may be configured to generate a second intermediate current in response to the first input voltage and the second input voltage. The third comparator circuit may be configured to generate an intermediate reference current in response to a first reference voltage and a second reference voltage. The difference circuit may be configured to generate a first compare voltage and a second compare voltage in response to the first intermediate current, the second intermediate current, and the intermediate reference current. The apparatus may indicate a squelch condition when the first compare voltage is greater than the second compare voltage.