Chip design of a 5.8-GHz fractional- N frequency synthesizer with a tunable G _m − C loop filter

Abstract

This paper proposes a novel Gm−C loop filter instead of a conventional passive loop filter used in a phase-locked loop. The innovative advantage of the proposed architecture is tunable loop filter bandwidth and hence the process variations of passive elements of resistance R and capacitance C can be overcome and the chip area is greatly reduced. Furthermore, the MASH 1-1-1 sigma-delta (ΣΔ) modulator is adopted for performing the fractional division number and hence improves the phase noise as well. Measured results show that the locked phase noise is −114.1 dBc/Hz with lower Gm−C bandwidth and −111.7 dBm/C with higher Gm−C bandwidth at 1 MHz offset from carrier of 5.68 GHz. Including pads and built-in Gm−C filter, the chip area of the proposed frequency synthesizer is 1.06 mm2. The output power is −8.69 dBm at 5.68 GHz and consumes 56 mW with an off-chip buffer from 1.8-V supply voltage.

Hybrid phase-locked loop with fast locking time and low spur in a 0.18-μm CMOS process

“…The tuning range of the VCO is PLLs in Refs. [2] and [3], the proposed hybrid PLL achieves lower reference spur level. The sub-sampling technology is employed in Ref.…”

“…Phase-locked loops (PLLs) have been widely applied to recover and synthesize the frequency and phase in versatile wireless devices and systems, including frequency synthesizers, clock generators, high-speed data communication, and power generation systems. [1][2][3][4][5] Low spur signal and fast locking time are two key requirements in nearly all applications of PLLs. The most straightforward way to suppress the reference spurs of a PLL is to reduce its loop bandwidth.…”

Bound states of spatially dependent mass Dirac equation with the Eckart potential including Coulomb tensor interaction

“…Equation (19) is convenient for obtaining the parametric NU solution. The outline of this method is given in Appendix A [30][31][32][33][34][35] (21) and further using Eq. (A7), we have…”

“…On the other hand, the Dirac equation with PDM has been found to be very useful in studying some physical properties of various microstructures [11][12][13][14][15][16][17][18]. Recently, there has been increased interest in searching for analytical solutions of the Dirac equation with PDM and with constant mass under the spin and pseudospin (p-spin) symmetries [19][20][21][22][23][24][25]. In their recent works Hamzavi and Rajabi have studied Dirac equation in 1+1 dimensions with scalar-vector-pseudoscalar Cornell potential for spin-1/ 2 particle under spin and pseudospin symmetries [26].…”