Title :
High effective Q CMOS crystal oscillator design
Author_Institution :
Fac. of Eng., Yokohama Nat. Univ., Japan
Abstract :
According to a narrowing of frequency bandwidth in communication systems, high C/N crystal oscillators are required. In this report, a design method of high effective Q CMOS crystal oscillators is proposed to achieve high C/N characteristics. The method is achieved by inserting a series capacitance between the output terminal of CMOS and the π-shaped feedback circuit. An example of design shows that the dissipation of the active circuit facing the crystal resonator can he reduced by a factor 1/25 and the effective Q can be increased by a factor 7. Thus the effectiveness of the design method has been shown. It is concluded that the present method is useful for achieving high C/N CMOS crystal oscillators
Keywords :
CMOS analogue integrated circuits; capacitance; circuit feedback; crystal oscillators; π-shaped feedback circuit; CMOS; active circuit; crystal oscillator; high C/N crystal oscillators; oscillator design; output terminal; series capacitance; Active circuits; Capacitance; Design methodology; Feedback circuits; Feeds; Filters; Frequency; Oscillators; RLC circuits; Resonance;
Conference_Titel :
Frequency and Time Forum, 1999 and the IEEE International Frequency Control Symposium, 1999., Proceedings of the 1999 Joint Meeting of the European
Conference_Location :
Besancon
Print_ISBN :
0-7803-5400-1
DOI :
10.1109/FREQ.1999.840783