A Simplified <i>G</i>_<i>m</i> − <i>C</i> Filter Technique for Reference Spur Reduction in Phase-Locked Loop

Abstract

This paper presents a wideband approach for L5 and S-band integer-N phase-locked loop (PLL) targeting Indian Regional Navigation Satellite System (IRNSS) applications. A reference spur reduction technique using a Gm−C filter is proposed. The reference spur is improved by 7 dB when compared with one without any Gm−C filter. The wideband integer-N PLL is designed and fabricated in UMC 65-nm CMOS process. The Gm−C filter block consumes 200 μA current. The wideband voltage-controlled oscillator (VCO) oscillates from 1.6 GHz to 3.2 GHz having a tuning range (TR) of 40%, achieving a best and worst phase noise of ≈−122 dBc/Hz and ≈−116 dBc/Hz at a 1 MHz offset, respectively.

Keywords

• <i>G</i>_<i>m</i> − <i>C</i> filter
• phase-locked loop
• reference spur
• phase noise