Investigation of high-speed pulse transmission in MCM-D

Experimental investigation of high-speed pulse transmission in an MCM-D modules has been carried out. By using advanced CMOS dice (74AC240) and a fast comparator (SP93 808), and high frequency MCM-D technology, it is demonstrated that a long aluminum lossy line (8.0 cm) can limit the maximum frequency of an MCM-D module. On the other hand, the maximum frequency is limited by the CMOS circuits when the line length is equal or shorter than 6.0 cm. For a 5.0-cm line, best pulse integrity is obtained when a 40- Omega series resistor termination is utilized. From the half fall time measured with the comparator, the estimated maximum clock frequency in the module is about 1 GHz for a 5.0-cm stripline with impedance matched termination. Crosstalk is negligible between parallel striplines with a 75- mu m pitch in the module. On the other hand, crosstalk in the module package is observed.>