Implementation of the ASDBLR straw tube readout ASIC in DMILL technology

The ASDBLR application-specific integrated circuit (ASIC) provides eight channels of low-noise low-power high-rate on-detector readout suitable for the ATLAS transition radiation tracker (TRT) at the large hadron collider. The TRT's unprecedented wire chamber readout requirements of a maximum hit rate per wire of 20 MHz and double-pulse resolution of similar to 25 ns with position resolution of better than 150 mum in a high radiation environment have been addressed in the design of the ASDBLR. A carefully tuned ion tail cancellation stage followed by an output sensing baseline restorer implemented in differential structures provides robust signal-processing combination compatible with the realities of ASIC design. Two comparators track the output of the signal-processing stage to provide tracking information from charged particles and evidence of higher energy transition radiation photons; their outputs are summed as current steps to form a differential ternary output. The ten-year total dose requirement for neutrons of 10(14) n/cm(2) and 1.5 MRad of ionizing radiation led to the implementation of this design in the radiation hardened DMILL process.