Littelfuse is making a long term commitment to the new hire and thus wants to be thorough in the interview process. It may take some time but respecting the process is needed and identifying way to stay engaged.
The access to a broad team during the interview process is an excellent indication of company workings, culture and provides the opportunity for the candidate to do as thorough a process as Littelfuse is doing; so take the opportunity to ensure the company is the right place for you.