How does your company "spec"components

[dcorley]

Does your company create a spec for each component even if it is a "buy" "off-the-shelf" item i.e. a smd chip 1% resistor. Or do you just use the suppliers datasheets and choose sources referencing that ??

 

[IRstuff]

Generally, not; it's not worth the expense, particularly since there's no leverage to change or control the performance.

Ideally, though, it would NICE if specs were done for each and every component, particularly with something that has a long lifetime. When parts go obsolete, it would nice to know what the desired performance was, so that substitute parts are more readily selectable.

TTFN

FAQ731-376

 

[dcorley]

thanks, what size and market area is your company, I am trying for a broad survey to use as support for not doing specs for commodity parts.

DC

 

[IRstuff]

miltary/aerospace

TTFN

FAQ731-376

 

[ScottyUK]

A previous employer in the chip & wire hybrid industry for the military & aerospace sector used to document things like integrated circuit and transistor dice because of the various bonding pad layout variations for functionally equivalent devices from different manufacturers which had a direct effect on the assembly process. SMD components such as capacitors and resistors were only documented in terms of physical case dimensions; specific components were identified by the manufacturer's code.


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If we learn from our mistakes I'm getting a great education!

 

[IRstuff]

As I indicated before, our biggest problem is figuring out what the spec might have been for a part designed in 20 yrs ago, and whether some new part will do the same job.

So there's definitely some desire to do a better job up front, but we don't get paid for that, but we do get paid to deal with parts obsolescence.

TTFN

FAQ731-376

 

[geekEE]

I've worked at companies that do a spec for each component. I think that makes sense as long as you don't overspecify a part. For example, a simple 5% resistor that is used to pull up a digital I/O line might only need a few lines in its spec, whereas a high-precision resistor might need a much longer spec.

I think the problem with using a manufacturer data sheet as a spec is that, a few years down the road, it's hard to determine which of the characteristics were the important ones to a particular application