A 350 $\mu$W CMOS MSK Transmitter and 400 $\mu$W OOK Super-Regenerative Receiver for Medical Implant Communications

Abstract

Recent advances in the medical field are spurring the need for ultra-low power transceivers for wireless communication with medical implants. To deal with the growing demand for medical telemetry, the FCC commissioned the Medical Implant 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-regenerative 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 sensitivity 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.

MRI-based communication for untethered intelligent medical microrobots

“…In our proposed microrobot, we use a photovoltaic cell as a power supply as presented in [18] while an ion-sensitive field-effect transistor (ISFET) could be exploited as a sensor and a miniature coil acts as a transmitter. The communication methods for in-vivo application are mainly investigated in the literature for medical implants [19][20][21][22][23][24] such as implantable pacemakers and defibrillators [20,25,26], insulin pumps [21], hearing aids [22] or robotic endoscopy [27][28][29][30]. For instance, Ghovanloo et al [19] developed a high-rate phase-coherent FSK modulation protocol, a wideband inductive link, and three FSK demodulator circuits which are used in wireless implantable neural micro stimulation.…”

“…The communication methods for in-vivo application are mainly investigated in the literature for medical implants [19][20][21][22][23][24], such as implantable pacemakers and defibrillators [20,25,26], insulin pumps [21], or hearing aids [22] or robotic endoscopy [27][28][29][30].…”

“…Bohorquez et al [23] present a 350μW FSK/MSK transmitter and a 400μW super-regenerative receiver architecture optimized for using in medical implants. The transmitter was implemented in CMOS 90nm technology.…”

A 2mW CMOS MICS-band BFSK transceiver with reconfigurable antenna interface

“…Different solutions have been presented in the past years. On the receiver side, superregenerative architecture using On-Off Keying (OOK) modulation is reported in [3], while Frequency Shift Keying (FSK) implementations using direct conversion or low-IF systems are presented in [4][5]. A dual-receiver system supporting both OOK and FSK has been also reported [2].…”

“…Direct modulation Binary FSK (BFSK) schemes using fractional-N synthesizers have been used due to their high digital content [3][4][5].…”