NBTI Impact on RF Front End in Wireless Sensor Networks

In wireless sensor network (WSN), the communication node is the heart of the whole system. Negative bias temperature instability (NBTI) is becoming one of the most important factors that decide the life time of node chips, especially with the feature size declining. In this paper, the NBTI impact on the front-end circuits in the WSN nodes is studied, such as voltage-controlled oscillator (VCO), charge pump (CP), low noise amplifier (LNA), and even the whole transceiver system. The circuit level NBTI degeneration models are built for the key modules and the entire transceiver. It is shown that the phase noise of the VCO will be deteriorated, the current mismatch of the CP and the noise figure of the LNA will both be increased, and the sensitivity and the adjacent channel selectivity (ACS) will be depressed by NBTI. The conclusions are proved by simulation results using HJTC 0.18 μm technology.