Hard to find datasheets - why do companies use those parts?

[obiwanjacobi]

The other day I had trouble finding the datasheet for a part that was used in a repair I was doing. That made me think of how that would work, how does that company decide to use that part when there is hardly any -or no- info to be found?

I do not mean custom chips that some larger companies will create, that is understandable. I mean chips from "normal' chip manufacturers...

Thoughts?

[Rerouter]

some of those style chips can have a legacy history, the supplier sent them out some samples with proper documentation at one time, they like them and continued using them, or they contacted a supplier, they recommended them, and with a minimum stock order met gave them the documentation,

This is different from poor documentation, as a large number of these suppliers for some items do not wish to deal with the general public, some have NDA's, some have minimum orders, in most of these cases you will have to talk to a rep via phone or in person to get all the info you want,

[cyr]

No info to be found, or no info available on the web to the general public?

Two completely different things.

[Cliff Matthews]

Many answers to that question sir... but one is:  Parts acquisition isn't always based on demand.
Some tech buyers look for small firms that go-under every year, and parts-bins are auctioned-off that never go to ebay. Lenco Electronics in Toronto sold-off tons of parts and I still have 10-kilos of parts in my shop to prove it.
So some designer can just look over stock levels and valuation sheets (and never question, why do we have so many) and just assume "hey we've got bucket-loads of these, I'll get my design out without breaking the bank - too easy".

[obiwanjacobi]

No info to be found, or no info available on the web to the general public?

That would be the general public / web. I did not call the manufacturer of the chip in question for instance...

But I don't understand that if you have the documentation for your parts why not put them online? Would that not increase the chance the your parts will get used by other companies and sold through retailers (digikey, mouser, farnel etc)..?

[McBryce]

Not all manufacturers want their parts sold in small quantities through Digikey / Farnell etc. Industry component buyers contact the manufacturer directly, order samples (with datasheets) for the prototypes and depending on what we decide to use then go out and do a deal with the manufacturer which could be for a few thousand or a few million parts. These manufacturers have no interest is selling single parts to hobbiests.

McBryce.

[Rerouter]

If a product of yours is currently end of life, or NLA, would you want to pay someone to dig through your old archives, verify the information as correct and have to host it for a product you no longer sell?

For current chips yes i can agree, again it comes down to, if the chip isnt selling in large quantity, nor expected to, why do i want to pay that guy to check it and upload it, or they have some deal with another buyer, so they have them, but they are keeping them quiet unless asked for,

with most of these things, you can find "something" on them if you dig deep enough, i myself had to try and dig up the programming datasheet for a panasonic cpu used in a subaru radio, lets just say i found enough, but i was in corners of the internet that no search engine could get you to,

[free_electron]

i remebmber having to fix a board from a washing machine in the mid 80's. there was a chip on it made by siemens. TCA280 i believe. plenty of brands used that. datasheet ? just a block diagram. nothing to be found. why ? siemens made that motor controller specific for washing machine motors.... their motors...  anyone buying a siemens washing machine motor got the details of the chip and the schematic.  anyone outside the machine manufacturers was left in the dust... no data avaialable.


these things were not ASIC, they are ASSP : application specific standard products.  unless you are someone designing with that component you can not get the data. sorry.

[djQUAN]

Not all manufacturers want their parts sold in small quantities through Digikey / Farnell etc. Industry component buyers contact the manufacturer directly, order samples (with datasheets) for the prototypes and depending on what we decide to use then go out and do a deal with the manufacturer which could be for a few thousand or a few million parts. These manufacturers have no interest is selling single parts to hobbiests.

McBryce.

This.

And also, product makers can contact manufacturers for a project that they have and the parts manufacturer will have a portfolio with recommended parts with basic specs suited for the design. Then once a part is decided, the manufacturer sends complete documentation and even evaluation boards to test. That's how we did it in my previous job. The parts are not simple basic ICs though. Usually they are special uC or application specific LSIs (HD video processing chips etc).