This thread is related to previous one:
Aaron Barerra is the TI Engineer most familiar with this design.
I replaced the BSO150N03MDG FETs with the AUIRFN8459TR. Same pin-out, dual FET pkg. The dimensions are slightly larger, but I could solder them right in where the previous FETs were.
The motor tries to turn in InstaSpin Lab 01b, but just fitfully moves a small fraction of a revolution. Here's a comparison of relevant characteristics:
|SUM110N06-3m9H||4V||200 nC||3.9mohm||45nC||15,800 pF||110A||160ns||Used in Texas Instruments' DRV8301-69m kit, but no longer available.|
|AUIRFN8459TR||3V||40nC||4.8 mohm||14nC||2,250 pF||70A||55 ns||Replaced BSO150n03MDG with these.|
|BSO150n03MDG||1.5V||12.6nC||20mohm||1.4nC||970 pF||9.3A||3.8 ns||Original transistor that was experiencing "shoot-through."|
The new issue I'm seeing is illustrated by the figure below. The yellow trace is the High side gate, and the blue trace is the Low side gate of a pair (Q1 & Q2).
The high-side gate should be going up to about 34V, and it is, but all that ringing means it's only turned ON for a short period.
Any ideas what's happening here?