Re: Frontend & Thermal Management HallD

["Fernando J. Barbosa" <barbosa@jlab.org>]

Hi Mitch,

You are correct in determining that the input protection required on the 
negative input (N) needs to be more robust than on the positive input 
(P). Your attached schematics make this clear. Given the area 
limitations that you mention, I concur with your suggestion.

The preamp cards will include additional protection as outlined on the 
card schematics. I am also considering adding PCB integrated spark gaps 
(arrestors) as another safety measure.

Thanks for your continued updates and best regards,
Fernando


Mitch Newcomer wrote:
> I have a question about the ratio of input protection required between 
> the negative and positive inputs.
> We usually try to put as much protection as reasonable without 
> limiting performance on the die, for
> for the DMILL (SOI) process protection was moderatly good, perhaps  
> .1mJ, for the ASDQ (bipolar
> bulk process)  it was sufficient to let the cards work without 
> external input protection.  (3000V with 560pF)
> although it was decided to keep protection on the cards anyway. See 
> attached. -- Mitch
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