A fast passive phase shift keying modulator for inductively coupled implanted medical devices

This paper presents an integrated modulator for inductively coupled biomedical telemetry. The circuit implements passive phase shift keying (PPSK) modulation and is designed to work at 13.56 MHz with a single pair of coils for both data transmission and power delivery. The data link can reach data rates up to 1/16 of the carrier frequency, i.e., 847.5 kbps in this case. To our knowledge, it is the fastest data rate achieved by a single wireless link used simultaneously for power delivery and communication in implanted medical devices. The circuit was fabricated in a 0.6-μm CMOS technology, occupies a silicon area of 0.7 mm² and dissipates about 2 mW from a 5 V power supply at full speed of operation.