[sdiy] SSM2164 protection

[Neil Johnson]

Hi David,

> So, I decided it would be a hassle to try and retrofit negative-rail
> protection to all the 2164s in my system.  Also, the idea of putting a
> resistor on the +V pin gives me willies, and I don't relish the  
> idea of
> having to lay out special power connections for that chip on all my  
> designs.

Ok, so you protect at the rack level, and assume that the individual  
power connections to your boards never, ever fail, and that when you  
fit them you will never, ever make a mistake.  If these modules are  
for your own enjoyment then do whatever you feel happiest with.

If, however, you're designing modules for production that will travel  
the world, to be fitted by customers who are not you, then I would  
suggest taking a more pro-active stance.

In light of these recent discussions I will be reviewing all of my  
SSM2164 designs and adding some sort of protection scheme, either a  
plain resistor or something more involved (PNP + zener), for the next  
board revisions.

Cheers,
Neil
--
http://www.njohnson.co.uk