JM Pichot wrote about the Signetics 9046:
Subject: What is a FINO?
FINO is First-In-Never-Out.
Can you explain me, what is Vff?
Is it a good idea to decrease this voltage in order to
Not really. If you decrease it sufficiently to extend the life of
the filament, the circuit won't function correctly.
But what will happen with our 50 Hz european supply?
You need to get the 50 Hz rated version of the part. Contact your
Signetics sales representative.