0.43-nJ/bit OOK Transmitter for Wearable and Implantable Devices in 400-MHz MedRadio Band

A low-power, spur-less ON–OFF keying transmitter (TX) is presented for biosignal communication in medical device radio communication band (401–406 MHz). A TX has been implemented as an optimally designed complementary n-channel metal-oxide–semiconductor and p-channel metal-oxide–semiconductor current reuse
$LC$
oscillator (LCO) with an extremely small size surface mount device inductor (SMDL) as the radiating element. An SMDL removes large size 50
$\Omega $
antenna from a TX at 400 MHz, which makes it suitable for wearable healthcare devices (WHDs) as well as implantable medical devices (IMDs). The proposed idea is proven with the LCO fabricated in 180 nm CMOS mixed mode technology. Measurement results show that the proposed TX radiates −49 dBm power by consuming 85
$\mu \text{W}$
power from 1.2 V supply. Energy usage of the TX is 0.43 nJ/bit at a data rate of 200 kb/s while meeting the spectral mask requirement of the band. Successful communication of biosignals has also been demonstrated with a commercial off the shelf receiver at a data rate of 200 kb/s with a BER
$<10^{-3}$
for a maximum distance of 2 and 1 m for WHD and IMD scenarios, respectively.