A novel mixed-signal self-calibration technique for baseband filters in systems-on-chip mobile transceivers

This paper presents a novel digitally-assisted automatic frequency tuning technique, and the self calibration technique is verified for a 130nm CMOS 4th order biquad baseband low-pass filter case with 20MHz cut-off frequency, which satisfies the typical LTE receiver specifications. The proposed tuning method includes hardware reduction methods, coherent sampling, and magnitude calculator using "alpha max plus beta min" algorithm for significant chip area reduction with negligible accuracy degradation. The cut-off frequency turns out to be tunable in the range of 16.2MHz to 24.4MHz, and the tuning error is less than 0.4% over the whole frequency tuning range. The estimated area consumption is 0.027mm2 with 80% device density, and power dissipation is 0.16mW at 128MHz clock speed with a 1.2V supply voltage.