A new coupling scheme for multiphase and quadrature signals generation

作者：Asyaei Mohammad^*

来源：Analog Integrated Circuits and Signal Processing, 2012, 73(3): 993-997.

DOI：10.1007/s10470-012-9940-6

• Cross-connected VCO
• Multiphase
• Phase noise
• Quadrature

A new coupling technique for low-phase noise low-power quadrature signals generation is presented. In the proposed technique two identical CMOS LC-voltage-controlled oscillators (VCOs) are coupled in an in-phase anti-phase manner via the substrates of the MOS varactors. Use of substrates (in other words the intrinsic gate-bulk capacitances) of the MOS varactors for coupling, results in elimination of any extra coupling elements and also their associated noises. Utilizing the proposed technique, a quadrature VCO (QVCO) is designed and simulated in TSMC 0.18 mu m RF-CMOS technology. The phase noise of the proposed LC-QVCO is -137.5 dBc/Hz at 3 MHz frequency offset from 5.4 GHz center frequency, while the total DC current drawn from a 1.8-V power supply is 8.37 mA. Generalizing the proposed coupling scheme to several identical LC-VCOs, low-phase noise multiphase signals can be generated. The proposed circuits can operate with power supplies as low as 0.6 V without any performance degradation.

• 出版日期2012-12