3.6-GHz 0.2-mW/ch/GHz 65-nm cross-correlator for synthetic aperture radiometry

Abstract

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.

A 3-GHz reconfigurable 2/3-level 96/48-channel cross-correlator for synthetic aperture radiometry

“…This section will outline features which go beyond the previous design [6] in order to address many of the current needs for synthetic aperture instruments.…”

“…Having single-ended inputs means the differential pair of the ADC can be split and connected to two cross-correlator ASICs with no need for additional splitter circuitry, except for the differential clock inputs. We use a data routing and clocking scheme that is similar to that used in the previous cross-correlator ASIC [6]. As shown in Fig.…”

“…Having 96 input channels corresponds to 4,560 correlation products (more than a doubling from 2,016 [6]). Each channel has been supplied with an input monitor (M) that counts the number of logic 1s, which in combination with an internal clock-pulse counter (CM) can be used to determine offsets for use in ADC calibration and post-processing correction.…”

“…The total layout area is 3.04 mm 2 , half of which is active logic. This constitutes a 2X improvement in efficiency in terms of logic area per correlation product compared to the earlier design [6]. With this more compact layout, data paths between correlation products are shorter, making it possible to downsize buffers to save power.…”

“…The cross-correlator presented here reuses the backbone architecture from an earlier 64-channel 2-level crosscorrelator [6], but supports new features, such as reconfigurability, channel monitors, and double buffering, and significantly improves on channel count, power efficiency, and readout speed. The cross-correlator can be configured in either a 2-level 96-channel or a 3-level 48-channel mode.…”