Major Considerations in System-Level Thermal Design of Next-Generation Telecommunications Equipment

The thermal management of next-generation telecommunications equipment is becoming more challenging than ever before, thanks to the elevated ambient temperature requirements (up to 65°C) from network carriers, and the thermal limitation of critical components such as optical transceivers (with a max. rating of 85°C). With thousands of watts of heat dissipation from a single shelf, a systematic methodology has to be developed at the planning stage so that every possible means to streamline the thermal management can be integrated into the system-level design. This paper uses a next-generation fiber-optic telecom product as an example to demonstrate the impact of some major mechanical/electrical parameters (such as fan curve, acoustic noise, air filter, copper content of PCB and baffles, etc.) on the thermal performance of the system. Each factor is quantitatively analyzed based on field tests, and good design practices are suggested.