Fully integrated low-power area-efficient FSK demodulator for inductively powered biomedical implants

A fully integrated low-power digital FSK demodulator is presented. Employing a novel clock extractor, the clock can be reliably retrieved from the FSK carrier, which also enables robust synchronisation of the clock and data without using a phase-locked loop. This implantable demodulator was fabricated in a 0.35 μm CMOS process and tested using inductively coupled coils.