Custom versus Cell-Based ASIC Design for Many-Channel Correlators

While ASICs are efficient in terms of area utilization, performance, and power dissipation, ASIC design requires significant development resources. We compare two approaches to implementing ASIC correlators for interferometric imagers and spectrometers: The first approach, custom design, gives very high performance and area utilization, but is complex and time consuming. The second approach, cell-based design, reduces design time, but leads to lower performance and area utilization. In our evaluation, we consider two different correlator architectures: Autocorrelators for spectrometry, and cross-correlators for synthetic aperture imaging. Based on both 65-nm CMOS and 28-nm FD-SOI process technologies, our results show that for implementations for a limited number of channels, the cell based approach may prove useful since it offers relatively short development time while still providing acceptable area utilization and performance. For larger designs, however, the area overhead of cell-based design becomes a major concern, especially for autocorrelator architectures.