Achieving ATE accuracy at gigahertz test rates: comparison of electronic and electrooptic sampling technologies

Testing devices at clock rates exceeding 50 MHz with waveform resolution below 100 ps necessitates the use of sampling methods. The current state of the art includes two radically different sampling technologies: electronic sampling (ES) utilizing a diode bridge structure and a novel electrooptic sampling (EOS) technology which uses short light pulses as the time-resolving element. The bandwidth, loading, and time/voltage accuracy of these two technologies are compared for fitness of use in a gigahertz ATE (automatic test equipment) environment. It is noted that the analysis of these two techniques quantifies the electrooptic technology´s time accuracy advantages due to its low loading and short DUT (device under test)/sensor distances