Digitally tunable active inductor for RF-DCO applications

Abstract

ABSTRACT The design of a tunable differential active inductor by employing a digitally controlled current source is presented in this work. The design proposes a 4-bit digitally tunable active inductor (DTAI) suitable for multi-band radio frequency-digitally controlled oscillator (RF-DCO) applications. This DTAI has been implemented in standard 180 nm complementary metal–oxide–semiconductor (CMOS) process with a 1.8 V supply, and its performance is analysed. The post-layout simulation results show that DTAI emulates an inductance tuning range of 4 nH to 55 nH with self-resonant frequency ranging from 4.3 GHz to 14.6 GHz. The noise performance of the design along with its power consumption for digital codes [0001 to 1111] is plotted. The maximum quality factor ranges from 4 to 5 without the negative compensation resistor, maximum noise is 1.9 nV/ and maximum power dissipation is 10.5 mW. The layout of the proposed design is drawn, the total area occupied is 48.16 µm x 16.6 µm. An example implementation of the proposed 4-bit DTAI as a DCO targetting RF applications is discussed.