Reference‐less wake‐up receiver with noise suppression and injection‐locked clock recovery

A reference‐less ultra‐low‐power wake‐up receiver (WuRx) is proposed for the highly integrated Internet of things applications. The WuRx utilises a direct radio‐frequency envelope detection technique with input synchronised switching to suppress 1/ f noise and enhance the sensitivity. Moreover, injection‐locked clock and data recovery circuitry is used to perform on‐chip clock generation. A prototype 2.4 GHz WuRx is designed and implemented with 90 nm complementary metal–oxide–semiconductor technology. The chip area is 1.0 × 0.95 mm 2 . The measurement results show that the WuRx consumes 25 μW and achieves a sensitivity of −51.5 dBm for 200 kbps data rate.