A low-cost QFP design for over 8Gbps SerDes applications with inductive return path co-planar waveguide built into the lead frame

In order to overcome large impedance discontinuities and crosstalk issues observed in the low-cost QFP, a new design scheme called inductive return path co-planar waveguide is proposed, which distributed circuit structure works a passive impedance equalizer at the same time reduces crosstalk necessary to achieve over-10Gbps signal transmission. The proposed design scheme has been applied to an exposed die-pad type TQFP, which has achieved successful 12.8Gbps differential signal transmission. Because this distributed circuit design needs only a small layout space, it is suitable to achieving compact and low-cost consumer device packaging. Additionally this design scheme is applicable not to only the TQFP but also to normal QFP.