The planned Phase-I and Phase-II upgrades of the LHC accelerator drastically impacts the ATLAS trigger and trigger rates. A replacement of the ATLAS innermost endcap muon station with a new small wheel (NSW) detector is planned for the second long shutdown period of 2019 - 2020. This upgrade will allow us to maintain a low pT threshold for single muon and excellent tracking capability even after the High-Luminosity LHC upgrade.
The NSW detector will feature two new detector technologies, Resistive Micromegas and small-strip Thin Gap Chambers. Both detector technologies will provide trigger and tracking primitives. The total number of trigger and readout channels is about 2.4 millions, and the overall power consumption is expected to be about 75 kW. The electronics design will be implemented in some 8000 front-end boards including the design of four custom front-end ASICs capable to drive trigger and tracking primitives with high speed sterilizers to drive trigger candidates to the backend trigger processor system. Tasks such as time, trigger and control signal distribution and readout are performed by the GBTx (Gigabit transceiver) ASIC, Slow Control ASIC, and an Front End Link Interface eXchange (FELIX) system. The overall design as well as studies with ASIC and board prototypes will be presented.