Silicon bipolar decision circuit handling bit rates up to 5 Gbit/s

A high-speed silicon bipolar decision circuit is presented which operates up to 5 Gbit/s. It may serve as a subcomponent for integration in a regenerator/repeater circuit for multi-gigabit fiber-optic trunk lines. The circuit was implemented in a standard bipolar silicon technology featuring oxide-wall isolation, 2-μm emitter stripe widths, and a transit frequency of 9 GHZ atV_{CE} = 1V. The measured clock-phase-margin of the decision circuit at 4 Gbit/s corresponds to two thirds of a bit slot and to half a bit slot at 5 Gbit/s. The minimum input sensitivity at 4 Gbit/s is less than 150 mV.