A Fully Integrated 1 kHz-1 MHz Sinusoidal Waveform Generator Based on Second Order Analog Interpolation

In single-chip electrical impedance spectroscopy systems, generation of sinusoidal waveforms with frequencies variable over several decades is often the most challenging task. In this work, we propose an original approach to sinusoidal waveform synthesis, based on second-order interpolation of sequences of discrete samples. Interpolation is performed in the analog domain, greatly relaxing the requirements for the digital sub-system. A prototype has been designed using a commercial 180 nm CMOS technology. Accurate simulation results showed that the proposed circuit is capable of producing sinusoidal waveforms with frequencies from 1 kHz to 1 MHz, 1 V peak-to-peak amplitude and sub-1% THD. Robustness of the solution is demonstrated with electrical simulations in the presence of bias voltage and temperature variations from nominal conditions, and with Monte Carlo simulations.