A high-precision 36 mm3 programmable implantable pressure sensor with fully ultrasonic power-up and data link

This paper presents the first fully ultrasonic (US) high-precision implantable sensor with active US links for power-up, data downlink, and data uplink. The packaged implant measures just 1.7×2.6×8.1mm
³
and includes a custom IC, piezoelectric devices (piezos) designed for data/power links, and a pressure transducer (PT). Characterization is performed at a large depth of 12 cm, in a phantom material, giving a >10× improvement over state-of-the-art in both the depth/volume and energy per sample figures of merit. The IC has a front-end and 10-bit ADC which achieves a pressure LSB of 0.78 mmHg and full-scale range of 800 mmHg, exceeding specifications required for various pressure monitoring applications. The sample rate is externally controlled, up to 1 kHz, through the downlink, allowing power optimization for various applications.