A 0.45-V Low-Power OOK/FSK RF Receiver in 0.18 $\mu\text{m}$ CMOS Technology for Implantable Medical Applications

A 0.45-V low-power 0.18 $\mu\text{m}$ CMOS OOK/FSK RF receiver for implantable medical applications is proposed. The receiver utilizes a wake-up mechanism to adjust its power consumption automatically by reading the amplitude of the input wireless OOK/FSK modulated RF signal directly. No additional wireless wake-up commands are required. Such a normally-off and instant-on scheme reduces the power consumption of this receiver significantly. The power consumption is 129 $\mu\text{W}$ in sleep mode and 352 $\mu\text{W}$ in wake-up mode. Other techniques, such as third-order-harmonic cancellation, subharmonic mixing, and forward body biasing are also adopted for better linearity, higher LO-to-RF isolation, and lower VDD, respectively. The measurement results show that the proposed receiver consumes only 2.6 nJ/bit (OOK) and 1 nJ/bit (FSK) to achieve the sensitivities of −55 dBm (OOK) and −53.5 dBm (FSK) in $\text{BER} constraint. The proposed receiver is designed for low-power and short-distance MICS band applications.