A 2.45GHz, 50uW wake-up receiver front-end with −88dBm sensitivity and 250kbps data rate

Abstract

This paper presents a 2.45 GHz wake-up receiver front-end intended for use in sensor networks, and is designed to receive data modulated with on-off-keying. Manufactured in 65 nm CMOS it employs an uncertain IF structure with threephase passive mixer and high gain amplifier chain. With the modulation frequency response tailored to the detector behavior, it achieves a sensitivity of −88 dBm at BER of 10 −3 with a data rate of 250kbps. Operating on a 0.75 V supply it has a power consumption of just 50 µW. It provides a 50 Ω input match completely on-chip using a compact inductor and has an active area of just 0.07 mm 2 .

A 915 MHz 175 $\mu \text{W}$ Receiver Using Transmitted-Reference and Shifted Limiters for 50 dB In-Band Interference Tolerance

“…), interference robustness of ULP receivers (RX) is a challenge in the limited power budget (~100µW) [1]. Several works [2][3][4][5][6][7][8][9] have been published recently for the implementation of ULP receivers. Reference [2] proposes a superheterodyne receiver combined with a low power Local Oscillators (LO).…”

“…However, the LO requires an external inductor to achieve good phase noise to avoid reciprocal mixing at low power, while non-linearity and limited RF filtering make it vulnerable to in-band interferers. To reduce the number of external components, Envelope Detector (ED) based receivers are proposed [3][4][5][6][7]. However, their selectivity and linearity are poor if an external high-Q filter is not used.…”

“…However, to obtain good sensitivity in such envelope detector based receivers, high gain Low Noise Amplifiers (LNA) are needed. Since these LNAs process the entire frequency band, strong in-band interferers will quickly saturate these LNAs, compressing the signal gain [4][5][6][7][8]. To break the trade-off between power, sensitivity and linearity, while improving the interference robustness, we propose an ULP receiver that uses two techniques: Transmitted-Reference (TR) modulation and Shifted Limiters (SL) [9].…”

On the human body communications: wake-up receiver design and channel characterization

“…In the U-IF architecture, the uncertainty of the IF is caused by the use of low-power RF synthesizer that suffers from poor stability. Sensitivity of −88 dBm and power consumption of 50 μW is reported in [22]. Sub-sampling-based WUR proposed in [25] is based on a differential sample and hold (S&H) circuit.…”

“…The WUR solutions are based on variety of different receiver architectures [7]: matched filter [11], radio frequency envelope detection (RFED) [12][13][14][15][16][17][18][19][20][21], uncertain intermediate frequency (U-IF) [22,23], sub-sampling [24,25], superregenerative oscillator (SRO) [8,9,26], and injection locking [27−29]. The design involves many tradeoffs; therefore, it is not straightforward to define, which architecture is best suited for a WUR.…”