Design of SIPC‐based complementary LC‐QVCO in 0.18‐μm CMOS technology for WiMAX application

Abstract

PurposeThe purpose of this paper is to design and realize a low‐phase noise, high‐output power, and high‐tuning range, fully integrated source injection parallel coupled (SIPC)‐based inductor‐capacitor (LC)‐quadrature voltage controlled oscillator (QVCO) covering WiMAX frequency range in 0.18‐μm deep submicron CMOS technology.Design/methodology/approachA pMOS based‐SIPC LC‐QVCO topology is realized with the center frequency of 2.58 GHz. On chip spiral inductor is integrated with substantial quality factor, Q coupled with underlying pattern ground shield (PGS) shielding. An enhanced tuning range is achieved by integrating the diode connected MOS‐based varactors. The CMOS‐based autonomous SIPC LC‐QVCO circuit was characterized for its output phase noise, tuning range and power spectrum response via wafer probing, utilizing a signal source analyzer (Agilent E5052 A).FindingsA quadrature oscillator catering to the needs of local oscillator (LO) generation covering the frequency range of WiMAX is realized. The parallel coupled architecture adapts direct source coupling, bypassing the LC resonator tank and relaxes the close in phase noise up‐conversion. The design consumes 2.19 mm2 of active chip area and measures a phase noise of −114.34 dBc/Hz at 1 MHz of offset frequency with 2.67 GHz of output frequency at 0.9 V of input tuning voltage. The corresponding output power measures to be −10.1 dBm, well suited for mixer hard switching. The design is realized in one poly, six metal 0.18‐μm standard CMOS technology.Research limitations/implicationsOwing to convergence discrepancy in the analysis, a diode‐connected MOS varactor is adapted in contrary to the accumulation mode MOS varactors with superior tuning range.Practical implicationsThe designed SIPC LC‐QVCO is of need in the generation of low‐phase noise, highly matched quadrature LO generation covering the WiMAX frequency range. The adapted parallel coupling also relaxes the voltage headroom limitation.Originality/valueThis paper shows how a fully integrated CMOS‐based SIPC LC‐QVCO architecture is adapted with low‐output phase noise and low voltage headroom consumption covering the WiMAX frequency range.