>>>> Again, assume that the wire coming in will have occasional short
>>>> spikes of 200V and figure out what that will do.
>>>
>>> When you say "short spikes", do you have an idea what "short" means?
>>> ns, us, ms range?
>>
>> I would want it to survive at 200V for a few 100uS.  You can assume the
>> repition of these events are low so that the average power can be ignored,
>> but the instantaneous spike must not damage anything.
> 
> 'my' clamp with 2 pnp + 2 npn transistors ? How close does the input have 
> to get to the power rails and still not be distorted ? The clamp allows 
> you to go to within 50mV of each rail for reasonably low input impedance.

I'd say in most automotive analog sensor applications, 50 mV is close
enough. They usually don't reach the rails for usable input.

Gerhard
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