Does an Atomic/Nuclear bomb have a lower bound for yield?

Factual Questions
1

I have no idea why this popped into my head in the middle of the night last night but…

Is there a lower threshold for the yield of a nuclear explosive device? I don’t mean in terms of economics or bang for the buck but is there a yield below which the device simply would not work. For example if I were to try to design a 0.5 KT bomb would I find out that under 2KT it’s just not possible?

2

A similar recent thread

3

Well I’ll be damned. I wonder if I saw that and had it stuck in my subconscious.
Hmmm…

Anyway - mods please feel free to close as this is a duplicate of another thread.