> The diodes I purchased are 1N5819 Schottky diodes:
> http://www.vishay.com/docs/94614/1n5819.pdf. The datasheet says
> "High frequency operation," but they might not be fast enough?

"fast" in this context applies to the reverse recovery time, rather than
a frequency

http://en.wikipedia.org/wiki/Flyback_diode

Past this point I'm no great expert, but I would guess that a 1N5819
is suitable if its temperature is limited. As Russell said, as a Schottky
heats up it becomes more conductive in the reverse direction and so
becomes useless as a diode, and in fact could be a liability

Filtering that suppresses heat-producing noise will help the diode
stay cool and reactive to fast transients
--=20
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