Where the limitations in charge capacity (maximum signal size) inherent with CMOS charge summing solutions are too restrictive, hybrid approaches where charge summing is combined with voltage or digital summing may prove interesting. As CMOS processes start to offer multi-pixel charge transfer capability, these hybrid architectures will become attractive solutions.
New CMOS TDI solutions
Piranha XL is Teledyne Dalsa’s high-performance TDI offering, built on a digital summation architecture. With high resolution and twelve lines, intrinsic noise levels are overcome with powerful on-chip processing. A significant engineering effort, much of the development required finding the right trade-offs between speed, artifacts and noise. With the digital summing, each of the twelve lines contributes to the high SNR in the light. The company continues to innovate and expects to announce a new family of charge-domain CMOS TDI imagers before the end of 2017.
As CCD continues to have a decreased market presence, and as CMOS technologies adapt to enable TDI applications, all of the technologies discussed above will play a role. Many engineering challenges still lie ahead to make CMOS-based TDI solutions. Some companies have made the mistake of betting on a single solution, ignoring the innate limitations of CMOS-based TDI. Teledyne Dalsa will continue to work on CMOS-based solutions, but will also continue to offer CCD-based solutions, knowing there will be demand for both technologies going forward.