Calibration Techniques for Low-Power Wireless Multiband Transceiver

Abstract

The low-power wireless transceiver is the basic silicon building block of wireless sensor networks and the internet of things. In this paper, two digital calibration and compensation techniques for low-power wireless multiband transceiver are presented to adjust the VCO's tuning curves in the frequency synthesizer and eliminate the DC offset voltage in the intermediate frequency (IF) pathway. The fuzzy binary search method is applied to VCO calibration, and gain-based DC offset cancellation (DCOC) is applied. Based on these proposed methods, a multiband transceiver is designed and fabricated in 0.18  μm CMOS with 1.8 V voltage supply. Experimental results show that with 24 MHz system clock, frequency synthesizer calibration can be completed within 450 without requiring any additional calibration prescaler, achieving a calibration resolution of 1 MHz; DC offset voltage can be reduced to less than 3.5 mV for 0 to 60 dB gain, with each calibration process taking only 1.28 ms time. The proposed techniques and corresponding circuits are proved to be cost-efficient while maintaining high performance, which is suitable for multiband and multimode transceiver integration.