A 67-μW Ultra-Low Power PVT-Robust MedRadio Transmitter

A 400 MHz narrowband MedRadio transmitter for short-range communication is presented. A new technique for PVT-robust, calibration- and regulation-free synthesis of the RF carrier is reported based on generating poly-phasors at 50 MHz with no power overhead. This is accomplished using a passive polyphase filter directly integrated within a crystal oscillator followed by an 8× edge combiner to synthesize the RF carrier with -109 dBc/Hz phase noise at 100 kHz offset. A dual supply, inverse class-E power amplifier is implemented for high efficiency at low output power (-17.5 dBm). Open-loop operation permits aggressive duty-cycling (<; 40 ns start-up time). State-of-the-art ultra-low power is reported from a prototype BPSK transmitter fabricated in 22 nm CMOS FDX when operated from a 0.4/0.2 V supply consuming 67 μW with 27% global efficiency.