Manufacturers have highly sophisticated simulation software, which tell them exactly all the design parameters and the entire statistics, if once a topology for the internal chip architecture was chosen. Therefore, finding a "TBD" in the datasheet can either mean, that the "datasheet" was written in an early state of design, where they didn't actually know how the topology shall look like or can mean, that they made a mistake somewhere.

Such a typical "TBD", which should make you run as fast as you can, is for instance the input offset voltage of a built-in analog signal comparator. This can be a really relevant parameter in an application, and having problems here means very probably, that the current die layout isn't proper yet. But, will they ever be able to clean-up the layout, so that a useful offset voltage can be provided??? Do we know that??

Once we had problems with a similar "TBD", which was the charge injection within a special chip. We also phoned the manufacturer and he promised a very little charge injection, but he couldn't adhere to it, finally.

A "TBD" in a datasheet can also mean, that the chip manufacturer is under time pressure and cannot spend enough time and efforts to design the chip properly.

So, whenever I see a "TBD" in a datasheet the warning bells are ringing...

Kai