Title :
A wide variable range VCXO for IC
Author :
Lee, Yuji ; Sasaki, Yoshinori ; Otsuka, Hideo ; Sekine, Yoshifumi
Author_Institution :
Coll. of Sci. & Technol., Nihon Univ., Funabashi, Japan
Abstract :
We suggest the use of a Miller capacitor as the variable capacitance circuit of the BJT-VCXO (VCXO using a bipolar junction transistor). When the external MOSFET´s gate-drain capacitance is 10 pF, we show that the BJT-VCXO using this variable capacitance circuit has a wide frequency variation of about 500 ppm. Also, we suggest the use of the MOSFET´s resistance change as the variable capacitance circuit of the CMOS-VCXO (VCXO using a CMOS crystal oscillator). When the external gate-drain capacitance is 30 pF, we show that the CMOS-VCXO using this variable capacitance circuit has a wide frequency variation of over 330 ppm
Keywords :
CMOS analogue integrated circuits; capacitance; crystal oscillators; variable-frequency oscillators; voltage-controlled oscillators; 10 pF; 30 pF; BJT-VCXO; CMOS crystal oscillator; MOSFET gate-drain capacitance; Miller capacitor; VCO; bipolar junction transistor; variable capacitance circuit; voltage controlled crystal oscillator; wide variable range VCXO; Bipolar integrated circuits; Bipolar transistor circuits; Capacitance; Capacitors; Diodes; Equivalent circuits; Frequency; MOSFET circuits; Voltage control; Voltage-controlled oscillators;
Conference_Titel :
Frequency Control Symposium, 1996. 50th., Proceedings of the 1996 IEEE International.
Conference_Location :
Honolulu, HI
Print_ISBN :
0-7803-3309-8
DOI :
10.1109/FREQ.1996.560246
