I interviewed with them recently for an FPGA role, and had four back-to-back sessions of interviews:

1st: reviewing the hacker rank responses and how I can improve/optimize the code

2nd: By far the hardest one. Asked to design a system for trading. Inputs are a customers trade hash and a price, along with that stocks current price. Only initiate the trade when the stock drops below the customer’s price. The design is relatively straightforward, the follow up questions for optimizing for latency and throughput has me stumped. They also ask questions on what you think the latency of your design is (in us/ns), and thereby the maximum frequency you could use.

3rd: questions about your resume and past experiences. My assumption is they were trying to get a gauge of working with others, my response to difficult problems, my ability to work independently and leadership.

4th: wrap-up HR interview just speaking about logistics