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A 4.8GHz Low-Phase Noise Quadrature Colpitts VCO Sheng-Lyang Jang , Yun-Hsueh Chuang , Chien-Feng Lee and Shao-Hua Lee 2006 International Symposium on VLSI Design , Automation and Test Page(s):1 - 4 April 2006. 系所 : 積體電路設計研究所 指導教授 : 林志明 學生 : 鄭士豪. Outline. ABSTRACT INTRODUCTION(1)(2)(3)
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A 4.8GHz Low-Phase Noise Quadrature Colpitts VCOSheng-Lyang Jang , Yun-Hsueh Chuang , Chien-Feng Lee and Shao-Hua Lee2006 International Symposium on VLSI Design , Automation andTestPage(s):1 - 4 April 2006 系所:積體電路設計研究所 指導教授:林志明 學生:鄭士豪
Outline • ABSTRACT • INTRODUCTION(1)(2)(3) • DESIGN OF QUADRATURE VCO A. Differential Colpitts VCO(1)(2)(3) B. Superharmonic Coupling Quadrature Colpitts VCO(1)(2) • EXPERIMENTAL RESULTS(1)(2) • CONCLUSIONS
ABSTRACT • current switching differential Colpitts –›low phase noise • superharmonic coupling –›quadrature signal generation • 0.18um TSMC CMOS technology for 4.8GHz • at 1MHz offset : –› phase noise : -120 dBc/Hz –› current consumption : 7mA –› power consumption : 12.6mW from 1.8V power supply
INTRODUCTION(1) • direct conversion radio transceivers –›low-power, low-cost, and highly integrated transceiver chips • quadrature voltage controlled oscillator(QVCO): –›I/Q-(de)modulation • several design options to generate the QVCO signals: 1. combination of VCO, polyphase-filter and output buffers . 2. VCO at double frequency followed by master slave flip flops . ref[2]
INTRODUCTION(2) 3. Two cross-coupled VCOs forced to run in quadrature by using coupling transistors. 4. superharmonic coupling.ref[3] 5. transformer coupled quadrature VCOs.ref[4] 6. quadrature VCO with back-gate coupling.ref [5] • LC QVCO consists of two parts: 1.two core LC VCO's –› the noise-shifting differential Colpitts VCO ref[6]
INTRODUCTION(3) 2. a coupling circuit for the two VCO's –›the superharmonic coupling technique.ref[3] –› This technique uses second-order harmonic coupling to enforce the quadrature relation between two oscillators. ●Using the cross-coupled pair LC VCO's to generate quadrature –› wide tuning range –› power consumption or phase noise don’t increase
DESIGN OF QUADRATURE VCOB. Superharmonic Coupling Quadrature Colpitts VCO(1)
DESIGN OF QUADRATURE VCOB. Superharmonic Coupling Quadrature Colpitts VCO(2)