A Clockless Temperature-Compensated Nanowatt Analog Front-End for Wake-Up Radios Based on a Band-Pass Envelope Detector

This paper presents an Analog Front-End for integrated Wake-Up Radios. The proposed Analog Front-End is composed of an envelope detector, a Schmitt trigger and a biasing block and has three distinctive features: i) clockless solution, which does not require an always-on oscillator; ii) an envelope detector with band-pass response which leads to smaller capacitance, thus easier integration, and low-frequency noise suppression; iii) temperature compensated biasing scheme. An active scheme for the detector is used based on MOSFETs operated in the subthreshold region with a self-biased topology. Advantages and drawbacks of the proposed architecture are analyzed. A prototype was fabricated in the STMicroelectronics 90-nm BCD technology. The overall power consumption, excluding the biasing block, is 36 nW at 1.2 V. A 10
^-3
Bit Error Rate is measured with a 771-MHz, 2-kbit/s OOK modulated input signal with -46 dBm power at room temperature and at -20 °C, and with almost -43 dBm power at 60 °C.