Transimpedance amplifier-based full low-frequency noise characterization setup for Si/SiGe HBTs

An experimental setup, based on current/voltage conversion through transimp edance amplifiers (TAs), has been implemented for the direct full low-frequ ency noise (LFN) characterization of Si/SiGe heterojunction bipolar transis tors (HBTs) in terms of base and collector short-circuit current noise sour ces. This setup performs a full characterization, as it measures simultaneo usly the two noise current sources and their correlation, thanks to an orig inal technique based on the specific properties of a specially designed buf fer amplifier using a low-noise common-base bipolar transistor (CB BJT). By means of translation formulae, the obtained measurements are compared with those carried out with a multi-impedance technique. They show a good agree ment both for the noise sources spectral densities and for their correlatio n. The TA-based setup provides enhanced capabilities In terms of measuremen t speed and remote control potentialities.