Getting aggressive with passive devices

The circuit boards of many mixed-signal and digital systems are now dominated by individually placed discrete passive (DP) components. This article looks at thin-film integrated passives (IPs) as an alternative to DPs in the effort to save board space and improve electrical performance and system reliability. Integrated passive components have been utilized successfully with ceramic substrate technology for over 50 years in the form of thick-film resistive and dielectric firable pastes. However, this considerable infrastructure cannot be transferred to FR4 and flex substrates due to the high firing temperatures required, and these board materials make up the vast majority of interconnect substrates, in consumer and commercial systems. Mmat has been lacking is thin-film IP materials and fabrication processes that are compatible with organic boards.