On 8/16/2011 11:49 PM, Mark Rages wrote:
> What is your input circuit like? How many volts will it take to damage=20
> it? It seems like you are clamping too low, and might have accuracy=20
> problems due to leakage. Maybe the current limiting resistors are=20
> sufficient, with clamps to supply rails. Regards, Mark markrages@gmail=20

I provided a bit more information in my other post, but in short this is=20
going to a current sense amplifier with a vss to input (common mode)=20
range of many volts (like 80).   The differential input voltage is a lot=20
lower (like 18V), and is also a lot more likely to be accidentally=20
exceeded due to things like a wiring error.  The correct way to do this=20
looks like a couple of series resistors, and some sort of bidirectional=20
TVSS diode across the input, say at 12V or less.

Clamps to supply rails won't work because of the high common mode input=20
range.  I basically have to clamp across the input.

-forrest


--=20
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