Comment by exmadscientist
6 months ago
> TI’s TXB0108 for this purpose as well, which has an automatic direction sensing feature that obviates the need for all of the direction logic that I mentioned above.
Yeah, don't use these guys. They have a tendency to swap translation direction in the presence of electrical noise, which means your input is now an output, cross-driving something. Sometimes everything survives just fine and switches back on the next edge. Sometimes the magic smoke comes out. And sometimes, if the stars align just wrong, you get an industrial accident.
This is one of those classes of parts that has hidden dangers and really should not be as prominently advertised as it is. They look simple, but they're for experts only. Don't use them unless you really know their failure modes and don't have another reasonable option.
These parts are bonkers. The ringing on its own outputs with a few inches of trace or (heaven forbid) a connector is regularly sufficient to self-trigger the automatic direction reversal. These things genuinely deserve the "experts only" label - they are close to unusable in the situations where you'd be most inclined to reach for them.
I've had them oscillate, though I don't remember the exact conditions, but they'd switch directions at very high speed, causing noise, causing them to oscillate.
Bunch of pulldown restrictions too, though if you pulled both ends the same way when not driven, that usually worked ok