Temperature-adaptive capacitor block and temperature-compensated crystal oscillator using it

Abstract

A temperature-adaptive capacitor array used in a TCXO so that the TCXO effectively conducts temperature-compensating in the resonant frequency without the non-monotonicity while a smaller silicon area is used in producing the capacitor array. A number of capacitor arrays allocated in two capacitor banks. Each of the capacitor arrays comprises two or more unit cells, and in turn each unit cell consists of a unit capacitor and a switching element, respectively. All of unit capacitors included in the capacitor arrays are connected each other through a decoder assembly to provide a crystal oscillator with a load capacitance. The unit capacitors belonging to one of the capacitor arrays have the same capacitance with each other. Two unit capacitors belonging to different capacitor arrays, however, have different capacitances from each other. The capacitance of the unit capacitors belonging to each capacitor array is set in consideration of control preciseness required in compensating a frequency deviation in the resonant frequency of the crystal oscillator as the temperature varies in at least a portion of a practical temperature range, within which the crystal oscillator operates.