Significant Improvement in SNR of PMUTs by Using Transimpedance Amplifier: A Promising Architecture Towards Canonical Ultrasound Medical Imaging

This paper represents a different approach to increasing the signal-to-noise ratio (SNR) of piezoelectric micromachined ultrasound transducers (pMUTs) during reception, instead of the typical low-noise voltage amplifiers used for classical bulk PZT ultrasound transducers. Since a pMUT is modeled as a current source in its equivalent electrical model, a transimpedance amplifier (TIA) with very low input impedance has been utilized to capture all the current produced by the pMUTs of one transducer channel and convert it into voltage. We demonstrated an improvement of 27 dB in the dynamic range of a pMUT array, easily achieving a total dynamic range of 70 dB. These results are significant as they make medical imaging with a pMUT array less dependent on the quality and performance of the piezoelectric thin film.