Modeling of lead-frame plastic CSPs for accurate prediction of their low-pass filter effects on RFICs

This paper presents a direct extraction method to construct the electrical models of lead-frame plastic chip scale packages for RE integrated circuits (RFICs) from the measured S-parameters. To evaluate the package effects on the reciprocal passive components, the insertion and return losses for an on-chip 50-Omega microstrip line housed in a 32-pin bump chip carrier (BCC) package were analyzed based on the established package model. Excellent ag reement with measurement has been found up to 15 GHz. When applied to the n onreciprocal active components, the gain variations for a heterojunction-bi polar-transistor array housed in an 8-pin BCC package have also been succes sfully predicted up to 22 GHz. Both cases have demonstrated that the packag e acts as a low-pass filter to cause a sharp cutoff for the RFIC components above a certain frequency.