A SiGe differential 50 ps Gaussian pulse generator for sub-sampling TDR measurements

A high-speed pulse generator with two complementary outputs has been realized in a SiGe bipolar technology. Both ultra-short output pulses (with different polarity) are well approximated by a Gaussian function and show a width t p of about 50 ps and an amplitude of 3.4 V, resulting in an amplitude at the differential output of 6.8 V. Such short pulses are essential in sub-sampling TDR systems as t p limits the bandwidth and thus the resolution of the measurement applications. The monolithically integrated pulse generator presented here shows substantial performance improvement compared to already existing solutions, mostly based on step recovery diodes.