An integrated circuit having an eye opening monitor (EOM) is provided. The integrated circuit may include: an internal circuit; and the EOM configured to measure an eye diagram of a predetermined point of the internal circuit, wherein the EOM may include a comparator configured to receive a first and a second parent reference voltages and a first and a second input voltages output from the internal circuit, and to compare the first and second input voltages with target reference voltages corresponding to the first and second parent reference voltages, and wherein the comparator divides the target reference voltages from the first and second input voltages respectively by varying a driving capability according to size information data, and compares the first and second input voltages with divided target reference voltages.