A rad-hard 2D-compressor ASIC for ALICE SDD experiment

CARLOSv3 is a custom digital integrated circuit that plays a significant role in the data acquisition (DAQ) chain of the silicon drift detector (SDD) of a large ion collider experiment (ALICE). Each CARLOSv3 acts as a JTAG switch for front-end electronics and implements on-line two-dimensional (2D) data compression for two 8-bit DAQ channels handling the data streams delivered by the SDDs. The chip has been implemented using the 0.25 μm CMOS 3-metal CERN-developed digital library. It is composed of nearly 10k gates, has 88 user pads out of a total of 100 pads, has a die size of 4×4 mm2 and is packaged in a CQFP100 ceramic package. In the paper, the chip is presented and described together with the 2D compression algorithm, the readout chain for ALICE SDD and the tests carried out.