US 9,813,044 B2
High gain filter circuit with an accurate transfer function
Marco Orazio Cavallaro, Catania (IT)
Assigned to STMicroelectronics S.r.l., Agrate Brianza (IT)
Filed by STMicroelectronics S.r.l., Agrate Brianza (IT)
Filed on Feb. 3, 2016, as Appl. No. 15/14,260.
Prior Publication US 2017/0222626 A1, Aug. 3, 2017
Int. Cl. H03B 1/00 (2006.01); H03H 11/04 (2006.01)
CPC H03H 11/0427 (2013.01) [H03H 11/0422 (2013.01)] 23 Claims
OG exemplary drawing
 
1. A filter circuit, comprising:
a second-order bandpass filter circuit having a differential input comprising an inverting input and a non-inverting input and a differential output comprising an inverting output and a non-inverting output;
a first feedback network comprising a first impedance circuit coupled between the inverting output and the inverting input and a second impedance circuit coupled between the inverting output and the non-inverting input; and
a second feedback network comprising a third impedance circuit coupled between the non-inverting output and the non-inverting input and a fourth impedance circuit coupled between the non-inverting output and the inverting input; and
wherein the second-order complex bandpass filter circuit is a leapfrog filter topology.