I've been doing similar research. According to this

Quote:

How long does it take to go from Term Sheet to signed contract?

It can vary greatly. From a couple of weeks if the deal is simple and if all parties are quickly aligned, to months for a complex deal: a heavy due diligence is needed, a legal restructuration is required, you have plenty of investors that you need to align, your cap table is messed up etc.

Quote:

Deal Finalization
Startup Due Diligence

## Some investors prefer to conduct the legal & business due diligences before emitting a Term Sheet. ##

A due diligence is simply the process of checking in details some particular aspects of a deal. Let’s say that the success of your company depends heavily on a unique technology that you have patented. Before making the investment and transferring their money to your bank account, the investor needs to check if everything was done properly on the IP side and if you are the real owner of this patent.

The due diligence process can cover many aspects from “legal” ones, how your legal entity is structured and if there are risks, to technology or HR ones, which are assessed by external agencies or the VC in-house team. That being said, at early stage the due diligence process should be light and “heavy” due diligences are an exception.