Case study of FPGA 7 series test socket - taking BGA238 as an example
Today's protagonist is the FPGA Artix-7 series chip - BGA238 chip. This chip has a size of 10*10mm and excellent performance. The serial rate is 211Gb/s and the memory channel is 1066Mb/s. It can be adapted to DDR3 memory. I /O voltage is also 1.2V~3.3V, suitable for multiple functions.
The production of the test socket first needs to consider the physical structure. The size mentioned earlier is: 10*10mm, the pitch is 0.5mm, and the ball array is a 19*19 array that is not fully full. This small pitch, large array of chips requires Use the alloy knob test seat to balance the reaction force brought by the probe. The current probe force is 20~30gf, and the force is mutual. Once there are more arrays, the total force will be very large, 238pin is 4780~ 7140gf, such a large force acts on the chip. In order to ensure uniform force and normal contact, the balanced pushing force of the knob is needed to ensure.
To solve the structural problem, it is necessary to consider the performance interoperability matching of the chip. It needs to match its speed, memory speed model and clock signal to determine the usage of the probe. Currently, the memory interface speed of this model is 1066Mb/s, and the serial speed is 211Gb/s, so just meet this requirement.
The structure and signals are already ok, and you only need to perform the next step of production. The actual finished product is as shown in the figure.
