OMEGA is in charge of the ASICs that generates very precise signals for the calibration of the ATLAS Electromagnetic Calorimeter at CERN.
CLAROC is one of the two ASICs that provide these calibration signals (the other one is LADOC). CLAROC is not a classical ASIC as it integrates only a few transistors but those are quite large in order to provide a current ranging from 5 µA to 320 mA with an accuracy of 1‰ and a reproducibility between channels of 2.5 ‰.
The circuit has four channels. Each one consists of current mirrors with a gain of 8 followed by a high frequency switch. When this switch is closed, a very precise current (set by LADOC ASIC) flows into an external RL network. When the switch is opened, the current contained in the inductor is sent to the electronic channel to be calibrated.
This circuit is realized in SOI CMOS 0.18 technology from XFAB (XT180). This technology ensures the radiation tolerance of the ASIC and also offers 10 V transistors necessary to provide large currents up to 320 mA on 25 Ohms.