A 90nm Passive RFID Tag's Custom Baseband Processor for Subthreshold Operation Below 0.3V

In the design of passive Radio frequency (RF) tags' baseband processor, subthreshold timing and wide-range-Process, voltage and temperature (PVT) variation problems are the bottlenecks to extend the tag's working range. A sophisticated processor is presented based on the EPC and ISO protocol. Power-aware ideas are applied to the entire processor, including data link portions. Innovatively, a novel custom ratioed logic style is adopted in critical logic paths to fundamentally speed up the circuit operations at ultra-low-voltage. The proposed baseband processor was fabricated in 90nm CMOS, another baseband processor design by regular standard-cell-based design flow was also fabricated for comparison. In measurement the proposed design indicates good robustness in wide-range supply and frequency variation and much more competent for subthreshold operation. It can operate at minimum 0.28V supply with power consumption of 129nW.