k...@att.bizzzzzzzzzzzz wrote:
> On Tue, 09 Oct 2012 16:39:23 -0700, Joerg <inv...@invalid.invalid> wrote:
>
>> k...@att.bizzzzzzzzzzzz wrote:
>>> On Tue, 09 Oct 2012 16:09:19 -0700, Joerg <inv...@invalid.invalid> wrote:
>>>
>>>> k...@att.bizzzzzzzzzzzz wrote:
>>>>> On Tue, 09 Oct 2012 13:53:04 -0700, Joerg <inv...@invalid.invalid> wrote:
>>>>>
>>>>>> k...@att.bizzzzzzzzzzzz wrote:
[...]
>>>> I know that IC mfgs provide lib parts at times. But I use a CAD that is
>>>> not so popular out here. It has its downsides such as this, but it has
>>>> an upside that wipes out any and all downsides: No crashes.
>>> It can't import data from any other format? Ours can't but I don't expect
>>> much from it (and I'm always disappointed).
>>>
>> It can import but let's put it that way: My experience with that is very
>> mixed. I wouldn't trust it.
>
> Trust, but verify. ;-)
>
:-)
Then it doesn't save time. If I have to verify all names, pin numbers
and ERC pin functions I might as well roll my own from scratch.
>>>>>>> ... OTOH, our CAD people demand that
>>>>>>> chips look on the schematic like they do on the board - no functional
>>>>>>> partitioning (except BGAs, for some reason).
>>>>>> I insist on the same, I really hate netlist-style schematics where the
>>>>>> front axle is on page 17 which the left front wheel it on page 32.
>>>>> Of course not. All the wheels go on page-1 (with the tires/wheels/and nuts in
>>>>> the hierarchy on page 2-5) and the Engine goes on page 12, with the exhaust on
>>>>> page 88.
>>>>>
>>>>>> Exceptions are logic gate and opamp multi-packs, of course.
>>>>> Gates and opamps are drawn symbolically but everything else is a single
>>>>> physical square box. UGH! It makes *really* ugly schematics. Impossible to
>>>>> follow.
>>>>>
>>>> That's in fact how most people want schematics. Including myself.
>>> Most? GOt a cite for that? None of the companies I've worked for wanted
>>> anything that ugly. It makes the schematic unreadable.
>>>
>> Most as in pretty much all my clients. I don't think there is any
>> opinion poll data for that available.
>
> Sorta my point, though if I'd shown up with a schematic like that, no one
> would have hired me. They want their documentation to describe how the widget
> works.
>
My schematics do describe how it works. Analog guys live that way.
>> I don't know what's ugly about it. Look at the schematics on the web,
>> they usually have opamps split out, same for 74HC14 inverters and such,
>> but the uC or DSP is one big block.
>
> Nothing else fits on the page with the "big block". Might just as well have a
> netlist.
>
That's perfectly fine. There will be a net name saying, for example,
PULSECNT and the two letters uC underneath. Then everyone with enough
smarts will know that this goes to sheet 7 where the big fat uC lives.
It is not necessary and would be rather confusing to whack out timer #2
and then place it on sheet 2 where this net is. You'd be looking at
sheet 7 and ask your self "There's pins missing here. Where the heck did
all the timers go?".
>>>>>> And I never
>>>>>> use large BGAs, those can spell doom in a hi-rel environment.
>>>>> Nonsense. I did a bunch of MIL stuff (Naval weapons system) with 1k pin BGAs.
>>>> On alumina and other higher tech material, yes. On FR4 I simply will not
>>>> do it. If the client insists, ok, but then the result is their
>>>> responsibility.
>>> Nope. FR4. The is *no* problem. In fact, they're more reliable than other
>>> packages.
>>
>> As you tend to say, I do not buy it.
>
> Of course you don't. It's a fact, though. BGAs are a far superior package.
> There are some problems with thick boards and fine-pitched BGAs but I try to
> stay at .8mm or above. .5mm can be done but it gets dicey with more than six
> layers or so. The boards get pretty thin, too (1mm and less).
>
The real fact is that whole small businesses have sprung up because of
all the BGA failures. Usually one-man shops. In our area their are
mobile, they often buy retired ambulances, put in a work bench, then
drive to the customers with the BGA problems.
>>> They do have to be done right, of course. ...
>>
>> Does this mean lots of laptop manufacturers including your former
>> employer do it wrong? This is how it looks when BGA solder joints on
>> their laptops give up:
>
> Probably. Nothing would surprise me from the PC Co.
>
>>
https://www.youtube.com/watch?v=Jpx4Rx4nVlM
>
> Sorry can't watch videos. My laptop will blow up. ;-)
>
It's an IBM T40 with BGA failure. Lots of other brands have the same issues.
>> Just for giggles, someone came up with a real low-tech repair method:
>>
>>
https://www.youtube.com/watch?v=3-ZFCsZB7T8
>>
>>
>>> ... Actually, at the PPoE
>>> (small company) they had far fewer problems with BGAs than they did with any
>>> other package. They didn't have an XRAY machine, either.
>>>
>>>>> Fine pitch isn't so good but there's nothing wrong with >.8mm BGA packages.
>>>>> Doom comes before the design starts, without them. No project = no paycheck.
>>>>>
>>>> Well, I am quite flooded with work despite the fact that I do not use
>>>> BGA. Simulating right now to see whether I can use an MSOP sans thermal
>>>> pad instead of a leadless QFN with pad. Nothing beats the gentle
>>>> compliance of leads on a package.
>>> You do tiny stuff. Without big DSPs, I don't have a job.
>>>
>> Then I do not want your job :-)
>
> Different strokes.
>
>>>> If it goes on like this through winter I won't need to heat the office,
>>>> the computer does that.
>>> Global warming is finally coming to CA?
>>
>> I sure hope so. However, since I do not trust that we bought the record
>> qty of five cords of almond again for this year. Blew through the
>> complete stack the last two seasons already, literally done to the last
>> sticks. In 2000 I thought that was impossible, back then two cords was fine.
>
> I thought you bought five cords last year? I've got two houses with heat
> pumps now. No more wood stoves for me (we do have a gas fireplace in the old
> house and I'll probably put gas logs in this one).
>
That's why I wrote "again". We bought five cords also last year, and
blew through all of that. Lots of people in CA also have heat pumps but
that was a major mistake. Because the state government became hardcore
leftist so now they tax the dickens out of these poor folks, via reverse
tiers on the power bill. A meager baseline quantity costs around
15c/kWh. With a heatpump or A/C you exceed that within days and then
prices quickly shoot up to something like 35c/kWh. I knew an old lady
who was very skinny, so needed it warm in the house in her 90's. She
paid north of $1000/month in winter. That's insane, I won't do that.