A Low-Power 0.4–2.3GHz NB-IoT UE Receiver with −15dBm OOB-Tolerant RF Front End

Abstract

This paper presents the system and circuit level design of a NB-IoT receiver (RX) based on 3GPP Technical Specification (TS) 36.101. This design targets serving many NB-IoT operation bands, so no off-chip filter is used. This dictates large linearity specification on the RF front end to avoid desensitization by −15dBm out-of-band blockers (OOBs). Large linearity specification leads to large power consumption. A solution is proposed to reduce power consumption of the RF front end, while achieving high gain and high linearity. The proposed RF front end provides 29.5dB gain and −10.9dBm IIP3 while consuming 2mW from a single 1.1V power supply. The solution includes adding gain programmability to conventional resistive feedback LNA to relax the trade-off between linearity and power consumption. The RF front end is designed using a 40nm CMOS technology and occupies an area of 0.2mm2.