A Highly Linear Range-Programmable CMOS Voltage Controlled Oscillator

• Main Authors: Sheng-Feng Lin, 林聖峯
• Other Authors: none
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/91232329438902335989

碩士 === 國立雲林科技大學 === 電子與資訊工程研究所 === 94 === Oscillators are key components of clock generator. One important performance parameter for voltage-controlled-oscillators is the linearity. In addition, wide output-frequency range and high operating speed increases the gain of the oscillator, especially in low-voltage operation. A highly linear CMOS transconductor or voltage-to-current converter is employed to implement a voltage-controlled-oscillator. A linear CMOS voltage-to-current converter is presented. PMOS transistors are employed in the resistor-replacement and voltage-level shifting of the proposed converter to avoid the body effect. To accurately annihilate the non-linear voltage terms, the substrate-bias effect of MOS transistors is treated more accurately in our design. Consequently, the non-linearity of the large-signal transconductance is reduced. For an input of 1Vp-p, the measured output total harmonic distortion is less than 1.2%. The transconductance varies by less than 0.5% in the input range.