Heat-Pipe Cooling Technology for High-Speed ATM Switching Multichip Modules

Tohru KISHIMOTO  Shinichi SASAKI  Katsumi KAIZU  Kouichi GENDA  Kenichi ENDO  

IEICE TRANSACTIONS on Electronics   Vol.E78-C    No.5    pp.564-573
Publication Date: 1995/05/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Instrumentation and Control
ATM,  multichip module,  heat pipe,  forced air cooling,  thermal design,  

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This paper describes an innovative heat-pipe cooling technology for asynchronous transfer mode (ATM) switching multichip modules (MCMs) operating with a throughput of 40 Gb/s. Although high-speed ATM link-wires are connected at the top surface of the MCMs, there is no room to cool the MCM by forced air convection, because power and the system clock signal are supplied by connectors on the rear and periphery of the MCM. We therefore chose to attach a cold-plate to the back of each MCM. The condenser part of the heat pipe, which is mounted behind the power supply printed circuit board, is cooled by low-velocity forced air. Total power dissipation is about 30 watts per MCM. With a 2 m/s foreced airflow, the sub-switching-element module (four MCMs) operates at a throughput of 80 Gb/s with a maximum junction temperature of less than 85. Measured thermal resistance between the switch LSI junction and air is about 6/W. This heat-pipe cooling system has a small system footprint, compact hardware, and good cooling capacity.