[sdiy] SSM2164 protection

[Tom Wiltshire]

On 2 Mar 2011, at 21:42, Neil Johnson wrote:

> 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

Out of interest, Neil, seeing as you've been sending SSM2164-based PCBs out all over the place, how many people have emailed you back saying "You know that PCB you sold me! Well, I soldered it up, plugged it in, and it smoked!"?

(My guess is none).

I'm not knocking the protection schemes that have been proposed (indeed, I've been following closely as a SSM2164 user myself), but I would like to suggest that the members of this list *might* be prone to getting more involved in a problem than it genuinely deserves. It's a continual hazard for enthusiasts. We tend to forget that normal people don't care as much as we do!

T.