A Distortion Shaping Technique to Equalize Intermodulation Distortion Performance of Interpolating Arbitrary Waveform Generators in Automated Test Equipment

This paper demonstrates a phase switching algorithm for Interpolating Digital-to-Analog Converter (DAC) based Arbitrary Waveform Generator (AWG) that resides in Automated Test Equipment (ATE) to test semiconductor devices. This confirms a previous exercise that was made by experiment with different Intermodulation Distortion (IMD) suppression techniques and starting phase shifts to suppress IMD tones of the AWG with the interpolating DAC. We show that the poor performance of the AWG can be improved by using the phase switching algorithm over the installed base of a company’s tester platform. It is also shown that the IMD performance of AWGs across a company’s tester installed base can be equalized, and how it can be achieved using the phase switching technique. We describe how the IMD specifications of the instrument are much worse than those actually measured, and by using phase switching, better performance can be achieved than what would be possible under normal conditions. We present how this technique allows the use of a low-cost tester resource to test IMD products of such as communication application ADCs with a higher dynamic range than what was previously possible.