A 350 /22W CMOS MSK Transmitter and 400 /22W OOK Super-Regenerative Receiver for Medical

Abstract

Recent advances in the medical field are spurring the need for ultra-low power transceivers for wireless communi- cation with medical implants. To deal with the growing demand for medical telemetry, the FCC commissioned the Medical Im- plant Communications Services (MICS) standard in 1999 in the 402–405 MHz band. This paper presents a 350 W FSK/MSK direct modulation transmitter and a 400 W OOK super-regen- erative receiver (SRR) specifically optimized for medical implant communications. The transceiver is implemented in 90 nm CMOS and digitally tunes 24 MHz in frequency steps smaller than 2 kHz. The transmitter meets MICS mask specifications with data rates up to 120 kb/s consuming only 2.9 nJ/bit; the receiver has a sensi- tivity better than 99 dBm with a data rate of 40 kb/s or 93 dBm with a data rate of 120 kb/s consuming 3.3 nJ/bit. A frequency correction loop incorporating the base-station is prototyped to eliminate the need for a frequency synthesizer in the implant while still achieving frequency stability of less than 3 ppm.