Abstract-A high-speed low-power cross-correlator ASIC has been implemented in a 65-nm CMOS process for the purpose of synthetic aperture radiometry from geostationary orbiting earth observation satellites. The chip performs cross-correlation on all individual signal pairs from 64 digital 1-bit inputs, which amounts to 2016 individual cross-correlation products. The experimental evaluation, using a specially developed PCB, demonstrates that the 3-mm 2 chip has a top performance of 3.6 GHz at a 1.2 V supply, at which it dissipates 790 mW.