An integrated circuit, in accordance with one embodiment of the present invention, includes a first device under test (DUT), a first ring oscillator, a second DUT and a second ring oscillator. The first DUT is biased such that interface traps are generated during a first mode. The generated interface traps result in a decrease in a first drive current of the first DUT. The second device under test is biased to maintain a reference drive current during the first mode. The operating frequency of the first ring oscillator, during a second mode, is a function of the first drive current. The operating frequency of the second ring oscillator, during the second mode, is a function of the reference drive current. The integrated circuit may also include a comparator for generating an output signal as a function of a difference between the operating frequency of the first and second ring oscillator.