| In this paper, design details of key building blocks for fast binary readout CMOS monolithic active pixel sensors developed for charged particle detection are presented. Firstly an all-NMOS pixel architecture with in-pixel amplification and reset noise suppression which allows fast readout is presented. This pixel achieves high charge-to-voltage conversion factors (CVF) using a few number of transistors inside the pixel. It uses a preamplifying stage close to the detector and a simple double sampling (DS) circuitry to store the reset level of the detector. The double sampling removes the offset mismatches of amplifiers and the reset noise of the detector. Offset mismatches of the source follower are also corrected by a second column-level DS stage. The second important building block of these sensors, a low-power auto-zeroed column-level discriminator, is also presented. These two blocks transforms the charge of the impinging particle into binary data. Finally, some experimental results obtained on CMOS chips designed using these blocks are presented. |
