| US 7,388,455 B2 | ||
| Film acoustically-coupled transformer with increased common mode rejection | ||
| John D. Larson, III, Palo Alto, Calif. (US); Naghmeh Sarkeshik, Cupertino, Calif. (US); and Stephen L. Ellis, Pleasanton, Calif. (US) | ||
| Assigned to Avago Technologies Wireless IP Pte Ltd, Singapore (Singapore) | ||
| Filed on Oct. 13, 2004, as Appl. No. 10/965,586. | ||
| Application 10/965586 is a continuation in part of application No. 10/699481, filed on Oct. 30, 2003, granted, now 6,946,928. | ||
| Prior Publication US 2005/0093659 A1, May 05, 2005 | ||
| Int. Cl. H03H 9/54 (2006.01); H03H 9/60 (2006.01) | ||
| U.S. Cl. 333—189 [333/192; 333/32; 333/25] | 22 Claims |
| 1. A film acoustically-coupled transformer (FACT), comprising: a first decoupled stacked bulk acoustic resonator (DSBAR) and
a second DSBAR, each DSBAR comprising:
a lower film bulk acoustic resonator (FBAR) and an upper FBAR, the upper FBAR stacked atop the lower FBAR, each FBAR comprising
opposed planar electrodes and a piezoelectric element between the electrodes, and
an acoustic decoupler between the FBARs;
a first electrical circuit interconnecting the lower FBARs; and
a second electrical circuit interconnecting the upper FBARs; in which:
in at least one of the DSBARs, the acoustic decoupler, one of the electrodes of the lower FBAR adjacent the acoustic decoupler
and one of the electrodes of the upper FBAR adjacent the acoustic decoupler constitute a parasitic capacitor; and
the FACT additionally comprises an inductor electrically connected in parallel with the parasitic capacitor.
|