Experiences and Lessons Learned from the End-of-Substructure card production of the ATLAS ITk Strip Upgrade

The silicon tracker of the ATLAS experiment will be upgraded for the upcoming High-Luminosity Upgrade of the LHC. The main building blocks of the new strip tracker are modules that consist of silicon sensors and hybrid PCBs hosting the read-out ASICs. The modules are mounted on rigid carbon-fiber substructures, known as staves in the central barrel region and petals in the end-cap regions, that provide common services to all the modules. At the end of each stave or petal side, a so-called End-of-Substructure (EoS) card facilitates the transfer of data, power, and control signals between the modules and the off-detector systems. The EoS connects up to 28 data lines to one or two lpGBT chips that provide data serialization and uses a 10Gbit s−1 versatile optical link to transmit signals to the off-detector systems. To meet the tight integration requirements in the detector, several different EoS card designs are needed. The power to the EoS is provided by a dedicated dual-stage DC-DC package providing 2.5V and 1.2V to the EoS cards. As the EoS production of almost 2000 EoS cards and accompanying DC-DC converters is getting close to completion, the production experience including detailed QC statistics and design validation (QA) results is reported on.