The ABCStar (ATLAS Binary Chip Star) is part of the ATLAS' Inner Tracker (ITk) upgrade. The ITk chipset is comprised of the ABCStar, HCCStar and AMAC chips. Each ABCStar must provide all functions required for the processing of signals from 256 strips of a silicon strip detector in the ATLAS experiment. It employs a binary readout. The architecture chosen for the ABCStar allows a multi-trigger data flow-control retaining the beam crossing synchronous pipeline transfer signal (L0) from previous versions, a first asynchronous read out request (PR) with priority and low latency (this signal is distributed to a fraction of the detector to get the tracking data participating in the L1 trigger) and a second asynchronous data readout request (LP) intended for a global readout. 

ABCStar was designed in 130 nm CMOS technology and employs radiation hardening techniques, such as ELT devices for the analog front-end and TMR techniques for the digital control logic. A photo of the chip is shown below.