Area optimized CORDIC-based numerically controlled oscillator for electrical bio-impedance spectroscopy

Abstract

A 10-bit Numerically Controlled Oscillator (NCO) based on the iterative architecture of COordinate Rotation DIgital Computer (CORDIC) optimized in terms of area is presented. The NCO was implemented in a TSMC CMOS 180 nm technology process. The design specifications were obtained from the requirements for applying Electrical Bio-Impedance Spectroscopy (EBS) to Cervical Cancer Detection (CCD). The architecture proposed was configured to generate 32 different frequencies for sinusoidal output signals in the frequency range of 100Hz up to 1MHz with maximum error of 0.00623% for frequency values obtained from the comparison of theoretical and experimental results. In terms of architecture, the IC area for the CORE circuit was 133μm × 133μm, 0.017 mm2. The designed IC was fabricated, mounted in a QFN48 package and tested into a custom PCB. For implementing comparative analysis in Altera FPGA EP3C5e144C8 — Cyclone III, experimental tests were carried out. A 78% area reduction was obtained with the implementation in the CMOS 180 nm TSMC process of Iterative Architecture in relation to the unrolled Architecture for CORDIC based NCO, which demonstrates the efficiency of a resource sharing technique.