An ultrasound imaging system (100). An exemplary system (100) includes a plurality of transducer elements (136) formed in subarrays (140) and a plurality of subarray circuit units (160'), with each circuit unit (160') connected to a subarray (140) of the transducer elements (136). The circuitry in each unit (160') comprises a plurality of integrated circuits (330, 340, 350), with at least a first (340) of the integrated circuits formed over a second (330) of the integrated circuits in a stacked configuration. In an example illustration the first integrated circuit (340) includes a first plurality of first bond pads (345) along a surface (342) thereof and the second integrated circuit (330) includes a second plurality of second bond pads (335) along a surface (331) thereof, with bond wires (344) extending between pairs of first and second bond pads to provide input/output signal connections therebetween.