A 0.6V and 0.53µW nonius TDC for a passive UHF RFID pressure sensor tag

This work presents a full passive UHF RFID pressure sensor tag which uses a nonius based TDC capacitive sensor interface. The proposed converter has a fully digital output and allows reducing power consumption while maintaining the required resolution. The nonius based TDC has been designed using TSMC 90nm standard CMOS technology. Post-layout simulations show that the converter presents a 12 bit resolution and 9 effective bits in the time range from 10μs to 40μs when V
_DD
varies in the range from 0.55V to 0.7V and temperature variations in the range from 0°C to 60°C are considered. The maximum measurement time is 49.9μs and the average power consumption of the converter is 0.53μW at 10 samples per second from a 0.6V voltage supply.