Pre-amplifier arrays for intra-oral ultrasound probe receiving electronics

In this paper, we present an array of pre-amplifier (16-channels) used in the receiving electronics of an intra-oral ultrasound probe, that forms part of a portable ultrasound imaging system. In general, this is a 2 stage amplifier, performing the task of minimising noise interference for the received ultrasound echoes and as the impedance converter between the transducer and beamforming stage. At the same time, it provides adequate gain at the centre frequency of 20MHz. The amplifier is capable of providing a -3dB bandwidth of 30MHz whilst driving loads equivalent to coaxial cables. The noise level and crosstalk are less than 10nV/√Hz and -16dB respectively at 20MHz for proper operation. The IC measures 4mm × 2mm and can be connected in series for application with more than 16 channels without affecting the pitch requirement of the transducer array.