一种应用于NB-IoT芯片的压控振荡器

Voltage-Controlled Oscillator Circuit for NB-IoT Chip

采用40 nm 1P6M CMOS工艺,研究与设计了一款应用于窄带物联网(Narrowband Internet of Things,NB-IoT)芯片的压控振荡器(Voltage Controlled Oscillator,VCO)。该VCO利用负反馈电路降低输出的相位噪声,通过电容减敏技术降低了输出频率相对于可变电容的敏感度,通过交叉偏置二极管技术提高了VCO增益的线性度。测试结果显示:VCO所需功耗为1.2 mW;当VCO震荡在3.49 GHz时,在偏离3.49 GHz的100 kHz、150 kHz、300 kHz、500 kHz和2.5 MHz的相位噪声的测量值依次为-92 dBc/Hz、-91 dBc/Hz、-100 dBc/Hz、-110 dBc/Hz和-125 dBc/Hz;采用此压控振荡器的NB-IoT发射机输出矢量幅度误差(Error Vector Magnitude,EVM)为7.8%,频谱辐射模板(Spectrum Emission Mask,SEM)和临近信道抑制比(Adjacent Channel Power Ratio,ACPR)均满足3GPP要求。可见,测试结果证明了所提出压控振荡器电路的有效性和实用性。

In this paper,a voltage controlled oscillator(VCO)for narrow-band Internet of things(NB-IoT)chips is studied and designed by using 40 nm 1p6m CMOS technology.The negative feedback circuit is used to reduce the phase noise of the output,the sensitivity of the output frequency to the variable capacitance is reduced by the capacitance desensitization technology,and the linearity of the VCO gain is improved by the cross bias diode technology.The test results indicate that the power consumption of VCO is 1.2 MW;when the VCO oscillates at 3.49 GHz,the phase noise measured at 3.49 GHz,100 kHz,150 kHz,300 kHz,500 kHz and 2.5 MHz is-92 dBC/Hz,-91dBC/Hz,-100 dBC/Hz,-110 dBC/Hz and-125 dBC/Hz in turn;the output vector amplitude error(EVM)of NB-IoT transmitter using this VCO is 7%,and the spectrum template(mask)and The adjacent channel rejection ratio(ACPR)meets the requirements of 3GPP.The test results indicate that the proposed VCO circuit is effective and practical.