A reconfigurable analog base-band amplifying filter for the Internet-of-Things based on Source Follower architectures

In the last 50 years, a lot of work has been made in order to develop what is now commonly known as Internet. The goal of internet has been to connect all the computing devices among each other, from desktop computer to smartphone. Now, more than half of the world population can connect to Internet and there are many efforts to increase this portion. Recently the challenge of "Internet-of-Things" (IoT) has been to connect not only computing devices but also all commonly used objects to each other. The current trend in technology shows that IoT has the potential to reshape how people interact with their daily environment. To enable the spread of IoT devices one key challenge is the communication among the devices. Wireless communication is, by the user standpoint, far more convenient with respect to traditional wired connections. However, wireless devices su_er from higher power consumption and lower data transfer rate with respect to the wired counterpart. In addition, reliability issues can come up when multiple devices try to communicate to each other. The analog front-end dominates the power consumption in current Integrated Circuits (IC) for wireless IoT. Therefore, it is critical to optimize the power consumption of this part. The next-generation WiFi standard (802.11ax) is one of the possible solution to these problems. It aims to increase the performance and the efficiency of data sharing among devices. The goal of this work is to design a Low-Pass Filter (LPF) for an analog receiver compliant with the 802.11ax standard. The designed block is a sixth order Chebyshev Type I LPF composed of three di_erent biquadratic cells, each one implementing a couple of complex-conjugate poles. The filter works in the high frequency range and it is capable to reconfigure its cut-off frequency between 10 MHz and 20 MHz. The Source follower (SF) architecture was used to implement the filter. The first cell is based on a new variant of the Flipped SF that is capable of amplification of the signal in the pass band. The second and third cells are both based on a new variant of the Super SF capable of obtaining very high quality factor. The filter was designed using the 28 nm technology provided by TSMC. The EKV model and Inversion-Coeffcient-based (IC) design methodology was used in order to target low power application. After post layout simulation, the _lter is compliant with the 802.11ax standard. The power consumption of the system ranges between 50 μW (for cut-off frequency of 10 MHz) and 120 μW (for cut-off frequency of 20 MHz). The total area of the system is 0.015 mm2.