A Fully Integrated Implantable pH Sensing SoC based on ISFET and Wireless Power Transfer Technology

With the changing pace of modern life, the incidence of gastrointestinal diseases has increased significantly. The implantable pH sensing SoC offers an efficient and convenient approach for real-time physiological monitoring. Nonetheless, traditional implantable pH sensing SoCs tend to be relatively bulky, and their operational duration is restricted due to battery limitations. In this paper, we proposed a fully integrated implantable pH sensing SoC. Based on the ion-sensitivity fieldeffect transistor (ISFET) and the wireless power transfer (WPT) technology, this system is CMOS-friendly. Benefiting from the integration of on-chip electrodes and an on-chip antenna, the size of the system is only 3 mm × 3 mm × 0.5 mm implemented in the 180-nm CMOS process. Sensor data is transmitted back to the TX node using backscatter telemetry technology. The chemical measurement results show that the sensitivity of this sensing SoC is 65 mV / pH.