Fair point - there's also the OPA211AID series that's "only" rated to 150 C
But even the $7-$8 a piece is far more dear than the $0.28 your budgeting.

I don't know what you're building, or what market segment it has to sell in=
,
but - to me at least - the temperature range you specified and the idea of
balking at $0.28 parts does _not_ belong in the same project.





Personally, I found it quite amazing that there are parts rated to operate
above the melting temperature of solder...

On Tue, Jul 10, 2018 at 11:14 AM, Jason White <
whitewaterssoftwareinfo@gmail.com> wrote:

> Hello Denny,
>
> I didn't mention it but actually the effective operating temperature is
> "around ~110C" I am actually more concerned with the -55C operating
> specification. If what you say is true then the slew rate would slow at l=
ow
> temperatures.
>
> I suppose I will have to reduce the peak-to-peak voltage of my 25kHz
> triangle wave to 1V to lower the slew rate requirement to ~1/10th the rat=
ed
> slew rate.
>
> I like the specifications on the OPA211 but I suspect price ($77 per chip
> vs $0.28/chip) may a limiting factor here.
>
> -Jason White
>
> On Tue, Jul 10, 2018 at 12:24 PM, Denny Esterline <desterline@gmail.com>
> wrote:
>
> > Interesting question. Unfortunately all I have is wild speculation.
> > A brief glance at the datasheet shows a bipolar output stage.
> > In general, bipolar passes more current and has higher leakage at
> > elevated temperatures. Into a fixed load, I would expect that to
> > increase slew rate.
> > Part of the problem is that the load and all the other parameters
> > have temperature dependencies as well. The combined effect is
> > very unpredictable. Be fun to build a test fixture and measure
> > it though.....
> >
> > The other thing I noticed in the datasheet is that the part is spec'd
> > to an absolute maximum junction temperature of 125 C.  Effectively
> > that means you cannot use it at an ambient temperature of 125 C
> > as it wouldn't be able to dissipate any heat. That may or may not be
> > a problem for you, depending on whether the 125C is a real spec
> > or a "marketing spec".
> >
> > I don't really know your application and design constraints, but a bit =
of
> > research found this one:
> > http://www.ti.com/product/OPA211-HT
> > Which has a slew rate of 27V / uS and is specified to a high temp of
> > 210 C !!! (holy s*!t)
> >
> >
> >
> >
> > On Tue, Jul 10, 2018 at 7:29 AM, Jason White <
> > whitewaterssoftwareinfo@gmail.com> wrote:
> >
> > > In my current design the operating temperature range is rather large:
> > -55C
> > > to 125C.
> > >
> > > I am planning on using the LM124DT from ST in an analog PWM circuit. =
My
> > > design uses a 0.5 to 4.5v triangle wave at 25kHz (required slew rate
> > > 0.2V/us).
> > >
> > > The LM124DT has a "typical" slew rate of 0.4V/us at 25C. A minimum sl=
ew
> > > rate is not specified and slew is not specified at other temperatures=
..
> > > Other manufacturers such as TI don't seem to specify this either.
> > >
> > > I would like to get an intuitive sense of how (or if) slew rate might
> > > change over temperature. Additionally I'd like to get some opinions a=
s
> to
> > > whether 0.2V/us could be too fast for the LM124.
> > >
> > > Thanks,
> > > Jason White
> > > --
> > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > > View/change your membership options at
> > > http://mailman.mit.edu/mailman/listinfo/piclist
> > >
> > --
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> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
>
>
>
> --
> Jason White
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
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