ECL I/O buffers for BiCMOS integrated systems: a tutorial overview

In this paper we describe the methodology for the design and layout of fast BiCMOS ECL (emitter-couped logic) I/O buffers. Principles of ECL circuit operation are described with emphasis on the NOR/OR gate and the bandgap voltage reference. A comparison of ECL 10 K and 100 K logic families is presented as well as complete designs for an input and output buffer. The pad macros are temperature- and supply-voltage-compensated and have nominal rise and fall times of 400 ps.