A Flexible Digitally Controlled Oscillator Structure to Reconfigure the Frequency Band in Multi-band RF AD-PLL System.

Reconfigurable architectures are more prominent in modern-day multi-band radio systems. This work has been conceptualized for a flexible 8-bit digitally controlled oscillator (DCO) design to suit reconfigurable RF all-digital phase-locked loop applications. To efficiently utilize the area, power consumption and attend to several operating frequencies, an optimal design of LC-tank based DCO topology with both L and C components contributing to the coarse and fine-tuning of the DCO's frequency of oscillation has been proposed. The design has been carried out in the Cadence Spectre RF tool with UMC180 nm technology. The proposed 8-bit DCO exhibits wide bandwidth, generating 240 oscillating frequencies in the LTE frequency band and occupies less area of 70 × 18 µm. The frequency of oscillation varies from 491.5 MHz to 3.392 GHz designed for an 8-bit digital control word with a tuning range percentage of 149%. The maximum phase noise obtained is −103.57 dBc/Hz @ 10 MHz offset causing a figure of merit (FOM) of −144.167 dBc/Hz. The total power consumed by the DCO ranges from 1.05 to 9.5 mW approximately. [ABSTRACT FROM AUTHOR]