"This apparently simple concept is very difficult to implement in CMOS technology since a true charge handling over several stages is normally not provided. This is whereour ESPROS Photonic CMOS process plays its strengths. In a pure CCD process, the core pixels could be implemented straightforward (in-fact a 2D CCD array does the job), but there is no performance analog circuitry available to gather, multiplex and amplify the incoming lines on one or few output pads at the required speed.
In close cooperation with a very ambitious customer, epc engineers created an implementation of the TDI concept in the ESPROS Photonic CMOS process. The challenging requirements were assessed using device simulation and optimum structures were selected for the test-chip, which is currently in production."