A film acoustically-coupled transformer (FACT) has a first and a second
stacked bulk acoustic resonator (SBAR 1, SBAR 2). Each SBAR has a stacked
pair of film bulk acoustic resonators (FBARs) and an acoustic decoupler
between the FBARs. Each FBAR has opposed planar electrodes and a layer of
piezoelectric material between the electrodes. A first electrical circuit
connecting one of the FBARs of SBAR1 to one of the FBARs of SBAR 2 and a
second electrical circuit connecting the other of the FBARs of SBAR 1 to
the other of the FBARs of SBAR 2. The first electrical circuit connects
the respective FBARs in parallel and second electrical circuit connects
the respective FBARs in series. A shunt inductor is included from the
reception path to ground.