26.5 A 0.7V 1.5-to-2.3mW GNSS receiver with 2.5-to-3.8dB NF in 28nm FD-SOI

We are approaching the age of IoE, in which wearable devices such as smart watches will be widespread. Sensing processors play a key role and the Global Navigation Satellite System (GNSS) is considered fundamental. Power consumption is one of the most important characteristics for such sensing processors. However, current GNSS receivers consume around 10mW [1,2] and are difficult to be embedded. GNSS receivers require high supply voltage for low-noise RF, which contributes to large power consumption. We developed 0.7V RF circuits that enable effective use of FD-SOI. Among the RF circuits, an LNA and an LPF are the key to 0.7V operation. We implemented an LNA with DC feedback using an OPAMP and an LPF that is composed of OTAs that have positive feedback as well as a mechanism for adjusting the output common-mode voltage.