A 2.4 GHz-91.5 dBm Sensitivity Within-Packet Duty-Cycled Wake-Up Receiver
Anjana Dissanayake, Henry L. Bishop, Steven M. Bowers, Benton H. Calhoun
Abstract
This article presents a highly integrated 2.4-GHz wake-up receiver (WuRX) achieving 91.5 dBm sensitivity with a state-of-the-art power and latency combination of 2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> at 100 ms. The proposed within-packet duty-cycling method employs a carrier-sense mechanism to turn off the WuRX early under idle channel conditions, which reduces the dc-power compared with conventional asynchronous packet-level duty cycling by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$9\times $ </tex-math></inline-formula> at 10 ms latency (21 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> ) and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times $ </tex-math></inline-formula> at 1 s latency (0.9 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{W}$ </tex-math></inline-formula> ) at the cost of 2 dB in sensitivity. The uncertain-IF topology with a phase-locked loop (PLL)-aided event-driven calibrated local-oscillator (LO) helps reduce the dc-power while maintaining a fast startup. The channel-embedded OOK scheme is used to create a deterministic IF to enable baseband (BB) channel selection and achieve continuous wave (CW) interference tolerance of −47 dB at 20 MHz offset. Fabricated in 65 nm CMOS, input matching and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$LC$ </tex-math></inline-formula> oscillator are all implemented on-chip, and operation is demonstrated with integrated low dropout regulators to capture the degradations in realistic system integration.