Early October the assembly of a new Gemini board called the Gemini-XH took place at Neways in Leeuwarden. More than 1000 parts ranging from 0.5 x 1 mm up to 50 x 50 mm had to be placed on this 340 x 144 mm 18 layer printed circuit board. The biggest challenge was placing the FPGA (field programmable gate array), a 50 x 50 mm component with 2892 solder balls. A 50 x 50 mm ball grid array is not a daily task for an electronic assembly company, e.g. not all pick and place machines are capable of components this size. After the reflow solder process, the assembly was verified using an X-ray scan to ensure that all connections are reliable.
The Gemini-XH, board developed by CSIRO, AUT and ASTRON, is equipped with a Xilinx Ultrascale+ VU37P FPGA. For this FPGA, high bandwidth memory (HBM) is integrated in the same package as the logic. This results in an increased bandwidth between the logic and 8 Gbyte of SDRAM to be used as short-term storage memory by the processing algorithm. With this upgrade of the Gemini board, the design of the hardware platform for the CSP-LOW Correlator Beamformer (CBF) is ready to be used for the SKA-LOW telescope.
© ASTRON