一种高线性度2.4GHz CMOS LC压控振荡器

A 2.4GHz CMOS LC Voltage-Controlled Oscillator with High Tuning Linearity

对影响压控振荡器(VCO)线性度的因素进行了研究,并提出了一种适用于2.4GHz ISM频段的高调节线性度的CMOS LC VCO结构。新的VCO结构采用两个控制端,分别控制一对p+/n-well变容管和一对MOS变容管。该VCO输出两个波段,调节非线性度分别为1.45%和1.74%,总调节范围为2.33～2.72 GHz,功耗为15mW,芯片面积为534×540μm2。结果表明,新的电路结构使得VCO的调节非线性度降低到通常只用一对变容管的VCO的一半以下,同时极大地减小了调节范围内相噪声的波动,有效地提高ISM频段内多种无线通信标准的射频收发机的性能。

A 2.4 GHz CMOS LC voltage-controlled oscillator （VCO） with high tuning-linearity for 2.4 GHz ISM band is presented. The VCO employs two controlling inputs： one controls a pair of p^＋/n-well varactors and another controls a pair of MOS varactors. Tuning nonlinearity is decreased by a factor of 2 and hence the variation of phase noise is significantly decreased compared with the VCO that uses a single pair of varactors. The VCO offers two frequency bands and has a total tuning range of 2.33-2.72 GHz. Its power consumption is 15mW and the chip area is 534×540 μm^2 in the TSMC 0.25 μm CMOS technology.