At 07:53 AM 1/12/01 -0800, James Newton wrote:
>Just go to
>http://www.njr.co.jp/e05/ee.htm
>then you can book mark it.

These chips (3717 etc) were originally Rifa chips, sold to ericsson, and
Unitrode It appears that they are going one more generation now.

Beware. There is a max chop frequency, and if you go beyond that, the chips
will crater when the H bridge blows through.  Ericsson didn't know anything
about this, probably because they didn't design it. The NJR datasheet
simply says that they don't reccomend above 40kHz because "current
regulation can be affected".

I'd call blowing a smoking crater in the chip "affecting" things...
This happens even at idle. In fact, I had it happen on a board while the
Ericsson rep was visiting, over this very problem. After much talking, and
sending them waveforms etc, in the end, they said they had "no idea" why
the chips were failing.

The Cherry CS3717 is a replacement that cherry designed, and they seem to
know a lot more about the chip as a result.

Allegro has one too, though the datasheet is a bit skimpy, they do seem to
have addressed this issue:
http://www.allegromicro.com/datafile/2917.pdf

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