C-less and R-less Low-Frequency ASK Demodulator for Wireless Implantable Devices

A miniature ASK demodulator without any passive elements, i.e., R or C, for implantable devices is presented in the paper. The noise margin of the envelope detector in the proposed ASK demodulator is enlarged such that any Schmitt trigger or current limiting resistor is no longer needed. It results in the number of transistors required for the ASK demodulator circuit is reduced to 12, while the area is merely 0.003025 mm² using 0.35 mum 2P4M CMOS process. The power consumption is found to be 1.01 mW by physical measurement on silicon.