RF Receiver Front End for 868.6-MHz Band IEEE 802.15.4 PSSS Standard

This paper presents an IEEE 802.15.4 868.6MHz band PSSS RF receiver front end. The wideband inductorless differential LNA, mixer and digitally controlled VGA based on multi-tanh principle with emitter degenerative configuration are implemented to fulfill the linearity requirement according to the PSSS standard. The test chip is implemented in a 0.25um SiGe BiCMOS technology. The LNA has a gain of 14dB with a 2.4dB NF at 868MHz. The noise figure varies between 2.35dB to 2.6 dB from 550MHz to 1.25GHz. The measured S11<;-10dB and S22<; -10 dB for the frequency range from 650MHz to 3GHz. Two-tone test measurements indicate a 5 dBm input third-order intercept point. The linearity is achieved with an overall receiver front-end gain of 60dB/10dB for input levels of -90dBm/-20dBm. The RF receiver front-end dissipates 12mA from a 2.5-V supply.