Autonomna i potpuno integrisana analogno-digitalna kalibracija i kompenzacija Čebiševljevog niskopropusnog UWB LC filtra petog reda

Abstract

Ovaj rad prikazuje projektovanje i optimizaciju Čebiševljevog niskopropusnog filtra petog reda sa kolom za autonomnu kalibraciju i kompenzaciju varijacije procesa na čipu. Filtar je realizovan u 130 nm RF CMOS tehnologiji i namenjen je za donji frekvencijski opseg UWB sistema. Predloženi kalibracioni koncept je potpuno integrisan, bez korišćenja spoljašnjih referenci. Kalibracioni koncept procenjuje vrednost kapacitivnosti linearnog MIM kondenzatora poredeći ga sa tačnijom MOS kapacitivnom referencom. Kako bi se procenila vrednost kapacitivnosti MIM kondenzatora, projektovan je oscilator niske učestanosti oscilovanja, koji koristi oba kondenzatora za generisanje oscilacija, jedan za drugim. Vrednost kapacitivnosti MIM kondenzatora je određena u digitalnom domenu na osnovu odnosa učestanosti oscilacija. Tačna vrednost kapacitivnosti linearnog kondenzatora se postiže kalibracijom kompenzacione banke kondenzatora u filtru. Predstavljena je detaljna matematička optimizacija kalibracionog procesa. RF, analogni i digitalni deo projekta su integrisani na test čipu i fabrikovani. Koncept je verifikovan kroz merenja na neupakovanom integrisanom kolu.

This thesis describes design and optimization of a Chebyshev 5th order low pass filter with included circuit for automated calibration and compensation of process induced variation of an on-chip capacitor. The filter is realized in 130 nm RF CMOS technology and is intended for thelower frequency band of a UWB system. The proposed calibration concept is fully integrated, without employing any of external references. The calibration concept estimates the value of a capacitance of a linear MIM capacitor by comparing it with a more accurate MOS capacitive reference. In order to estimate the capacitance value of the MIM capacitors a low frequency oscillator has been designed which uses both capacitors to generate oscillations, one after the other. The capacitance value of the MIM capacitor was determined in the digital domain based on the oscillation frequency ratio. The exact value of the capacitance of the linear capacitor is achieved by calibrating filter capacitor compensation bank. Detailed mathematical optimization of the calibration process has been presented. RF, analog and digital parts of the design have been integrated on the test chip and fabricated. The concept was verified by on wafer measurements.