A /spl Sigma/-/spl Delta/ fractional-N frequency synthesizer using a wide-band integrated VCO and a fast AFC technique for GSM/GPRS/WCDMA applications
- 28 June 2004
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Journal of Solid-State Circuits
- Vol. 39 (7) , 1164-1169
- https://doi.org/10.1109/jssc.2004.829938
Abstract
A fractional-N frequency synthesizer (FNFS) in a 0.5-/spl mu/m SiGe BiCMOS technology is implemented. In order to operate in a wide-band frequency range, a switched-capacitors bank LC tank voltage-controlled oscillator (VCO) and an adaptive frequency calibration (AFC) technique are used. The measured VCO tuning range is as wide as 600 MHz (40%) from 1.15 to 1.75 GHz with a tuning sensitivity from 5.2 to 17.5 MHz/V. A 3-bit fourth-order /spl Sigma/-/spl Delta/ modulator is used to reduce out-of-band phase noise and to meet a frequency resolution of less than 3 Hz as well as agile switching time. The experimental results show -80 dBc/Hz in-band phase noise within the loop bandwidth of 25 kHz and -129 dBc/Hz out-of-band phase noise at 400-kHz offset frequency. The fractional spurious is less than -70 dBc/Hz at 300-kHz offset frequency and the reference spur is -75 dBc/Hz. The lock time is less than 150 /spl mu/s. The proposed synthesizer consumes 19.5 mA from a single 2.8-V supply voltage and meets the requirements of GSM/GPRS/WCDMA applications.Keywords
This publication has 8 references indexed in Scilit:
- A 2-GHz wide band low phase noise voltage-controlled oscillator with on-chip LC tankPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2004
- A single-chip quad-band (850/900/1800/1900 MHz) direct conversion GSM/GPRS RF transceiver with integrated VCOs and fractional-n synthesizerIEEE Journal of Solid-State Circuits, 2002
- RF-CMOS oscillators with switched tuningPublished by Institute of Electrical and Electronics Engineers (IEEE) ,2002
- A 1.1-GHz CMOS fractional-N frequency synthesizer with a 3-b third-order /spl Delta//spl Sigma/ modulatorIEEE Journal of Solid-State Circuits, 2000
- Design issues in CMOS differential LC oscillatorsIEEE Journal of Solid-State Circuits, 1999
- A 27-mW CMOS fractional-N synthesizer using digital compensation for 2.5-Mb/s GFSK modulationIEEE Journal of Solid-State Circuits, 1997
- Delta-sigma modulation in fractional-N frequency synthesisIEEE Journal of Solid-State Circuits, 1993
- A multiple modulator fractional dividerIEEE Transactions on Instrumentation and Measurement, 1991