Have you ever been bitten by this policy, Bob?

I have definitely had people choose alternates for passives which were
problematic. For example, ceramic capacitors can vary in their voltage vs
capacitance variation. You can have two, say, 10uF, 0805, 25V ceramic caps
and one of them might have 6uF at 10V and another might have only 2uF at
10V.

I've also had problems with connectors where cheap knockoff connectors
didn't have the right plating and had much higher contact resistance (high
current battery connectors in this case).

Sean


On Tue, Jul 10, 2018 at 5:50 PM, Bob Blick <bobblick@outlook.com> wrote:

> Hi Denny,
>
> Some CMs are easier than others, but I've always managed to get them to g=
o
> along(for most parts). I always specify at least one manufacturer and
> corresponding part number(s), but I also have "ANY" and "EQUIVALENT P/N"
> listed. That way, if they feel uncomfortable substituting, they can go wi=
th
> a spec part. And they know that if the price isn't good enough, you'll be
> taking that job to the CM that gave a better bid.
>
> I don't spec ANY for things like inductors, connectors, LEDs, etc.
>
> Cheerful regards, Bob
>
> ________________________________________
> From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of
> Denny Esterline
> Sent: Tuesday, July 10, 2018 1:54 PM
> To: Microcontroller discussion list - Public.
> Subject: Re: [EE] LM124 Slew Rate vs Temperature? (-55C to 125C)
>
> >
> > <Snip>
> >
>
>
> > To save money I always try to specify "any" manufacturer, so my design
> > needs to allow for wide variations. Lately I've seen ST branded parts
> being
> > used.
>
>
>
> > <snip>
> >
>
> How do you manage to specify that and have board houses actually build it=
?
> I have a board house that I've tried doing exactly that with simple
> passives, and it's always a mess.
> The last BOM specified "1k ohm 5% tolerance or better, 0805 size resistor=
 -
> any manufacturer"
> and it resulted in three calls from them asking if XX was acceptable and
> eventually them wanting me to authorize it in writing. Turned into a bit =
of
> a fight and eventually
> they claimed that they "have to have a MFG part number, it's part of thei=
r
> ISO requirements".
>
> --
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