The present disclosure provides a transducer assembly. The transducer assembly includes a flex circuit. The transducer assembly also includes a first substrate that includes a piezoelectric micro-machined ultrasonic transducer (PMUT). The transducer assembly further includes a second substrate that includes an Integrated Circuit (IC) device. At least one of the first substrate and the second substrate is bonded to the flex circuit through wire bonding or through flip-chip.