Heat-Pipe Cooling Technology for High-Speed Atm Switching Mcms

Abstract

This paper describes an innovative heat-pipe cooling technology for high-speed ATM switching MCMs operating with a throughput of 40 Gb/s. Although high-speed ATM link wires are interconnected on the top surface of the MCMs, there is no room to coot the MCM by forced air convection, because the power and the system clock signal are supplied by the connector on the back side and peripheral of the MCM. We therefore attach a cold-plate to the back of each MCM. The condenser parts of the heat pipe, which is mounted behind the power supply printed circuit board, are cooled by low-velocity forced air. Total power dissipation including the power dissipation of the termination resistors is about 30 watts per MCM. With a 2 m/s forced air flow, this sub-switching element module operates at a throughput of 80 Gb/s (including 4 MCMs) with maximum junction temperature of less than 85 /spl deg/C. Measured thermal resistance between the switch LSI junction and air is about 6 /spl deg/C/W at an air flow of 2 m/s. This heat-pipe cooling system has small system footprint, compact hardware, and good cooling capability. We, demonstrate its effectiveness in cooling high-speed ATM switching MCMS operating with a throughput of 40 Gb/s.