For our valuable partner in the networking segment, we have created a layout and designed a passive heat sink for a server-based PCIe card.
The card is used in three segments: as a processor accelerator, network security, deep packet inspection card, and trading card for the stock exchange.
Our Task and Challenge
Our customer, well versed in designing SW/FW for off-the-shelf PCIe cards, realized that the market did not cater to all the high-speed functionality required. At the same time, Xilinx released new Ultra-Scale FPGAs that were the first that broke the magical barrier of 100 Gbps per transceiver.
They felt confident in HW design, but the layout and thermal management of such a card is a challenge even for experienced teams.
This fact has led to us being approached as a partner who can carry the product through the industrialization process to the running assembly line.
As the board was designed to cover several market segments, the component density was high, and the FPGA was in one of the most extensive packages for that family.
Mounting the heat sink while maintaining good contact with the cooled components and limiting the fixing elements that take up precious space on the board turned out to be another mechanical challenge.
A list of these components, together with the expected airflow in the server, served as an input for thermal analysis.
Regarding placement, there are many, usually conflicting, requirements of HW designers, layout engineers, and thermal engineers. It takes time and a lot of experience to find compromises by weighing up which requirements are “must have” and which are “should have.”
After weeks of design and simulations and several placement iterations, we have created a placement that fulfilled the requirements of all involved parties, selected proper material for heat transfer from the packages to the heatsink, and designed the heatsink and its mounting. The heatsink design was unique because cooling SFP cages was not possible with standard fins, so the thermal design had to take this constraint into consideration.
In the network segment, it is essential to save the server spaces and minimize failure by not using moving components. We designed a low-profile single slot PCIe 2 x 100Gbps communication card with a passive heatsink.
How It Is Made
The first challenge when we won the project was selecting the material for the PCB. Although the situation has improved since we finished this project, finding a PCB manufacturer that can manufacture boards designed for 100 Gbps transceivers is still challenging. The second challenge was the placement of components because the board coverage density approached physical limits.
The result was a low-profile PCIe card with the following parameters:
Our client operates and develops the national e-infrastructure for science, research, and education which encompasses a computer network, computational grids, data storage, and a collaborative environment. It offers a rich set of services to connected organizations.
In 2016-2017, we cooperated on the schematic design and created a PCB layout of the low-profile PCIe card. We also conducted thermal analysis and designed a passive heatsink for this card.
Since the foundation of Consilia in 2004, we have finished and supported dozens of projects.
ready to assist you
Consilia has a workforce of 30 developers in the competence fields of software development, software testing, hardware design, RF design, FPGA design, DSP design, and PCB design.