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Crystal solution for full Automotive temp range

Started by Ulf Samuelsson April 24, 2007
Anyone knows of manufacturers of 8 MHz  crystals specified for -40'C - 
+125'C?

-- 
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB 


"Ulf Samuelsson" <ulf@a-t-m-e-l.com> skrev i meddelandet 
news:f0lqhv$h4o$1@aioe.org...
> Anyone knows of manufacturers of 8 MHz crystals specified for -40'C - > +125'C?
google://crystal oscillator automotive/ gave the answer
> > -- > Best Regards, > Ulf Samuelsson > This is intended to be my personal opinion which may, > or may not be shared by my employer Atmel Nordic AB >
Ulf Samuelsson wrote:

> Anyone knows of manufacturers of 8 MHz crystals specified for -40'C - > +125'C? >
If you are having a hard time finding anything suitable within your Google search hits I'd contact a vendor. Since you are in Europe maybe these guys: http://www.kvg-gmbh.de/ http://www.quarztechnik.com/ http://www.jauch.de/ Personally I am not a great fan of using crystals in environments that shake a lot though. -- Regards, Joerg http://www.analogconsultants.com
"Joerg" <notthisjoergsch@removethispacbell.net> skrev i meddelandet 
news:HlwXh.85$tp5.61@newssvr23.news.prodigy.net...
> Ulf Samuelsson wrote: > >> Anyone knows of manufacturers of 8 MHz crystals specified for -40'C - >> +125'C? >> > > If you are having a hard time finding anything suitable within your Google > search hits I'd contact a vendor. Since you are in Europe maybe these > guys: > > http://www.kvg-gmbh.de/ > http://www.quarztechnik.com/ > http://www.jauch.de/ > > Personally I am not a great fan of using crystals in environments that > shake a lot though. >
You use a resonator, crystal oscillator or what? -- Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB
"Ulf Samuelsson" <ulf@a-t-m-e-l.com> wrote in message 
news:f0lqhv$h4o$1@aioe.org...
> Anyone knows of manufacturers of 8 MHz crystals specified for -40'C - > +125'C? > > -- > Best Regards, > Ulf Samuelsson > This is intended to be my personal opinion which may, > or may not be shared by my employer Atmel Nordic AB >
I only know a source for USA.. www.fmi-inc.com -70 to +200 degrees Celsius range..
  "TheDoc" <thedoc@future-solar.com> wrote:

  > www.fmi-inc.com

  > 70 to +200 degrees Celsius range.

  Interesting. Their life test is 2,000 hours. That is not long.

  The frequency  range is specified at DC to 300MHz. A crystal  for DC
  will be quite large.

  The temperature limit changes. It is -100C to +250C in

  http://www.frequencymanagement.com/_images/homePage/FMI_ET%20Rev3.pdf

  and -100C to +300C in

  http://www.frequencymanagement.com/FMI_ET%20Mini%20R5.pdf

  Regards,

  Mike Monett
Ulf Samuelsson wrote:

> "Joerg" <notthisjoergsch@removethispacbell.net> skrev i meddelandet > news:HlwXh.85$tp5.61@newssvr23.news.prodigy.net... > >>Ulf Samuelsson wrote: >> >> >>>Anyone knows of manufacturers of 8 MHz crystals specified for -40'C - >>>+125'C? >>> >> >>If you are having a hard time finding anything suitable within your Google >>search hits I'd contact a vendor. Since you are in Europe maybe these >>guys: >> >>http://www.kvg-gmbh.de/ >>http://www.quarztechnik.com/ >>http://www.jauch.de/ >> >>Personally I am not a great fan of using crystals in environments that >>shake a lot though. >> > > You use a resonator, crystal oscillator or what? >
First I think really hard about whether the app really needs a precise clock. Surprisingly often you can get away with ratiometric tricks and a LC or even RC oscillator, or a trimmed internal clock like the MSP430F2xxx family offers. Maybe Atmel has that feature as well. Rugged resonators is the 2nd path but, of course, usually you still don't get crystal accuracy. http://www.avxcorp.com/docs/techinfo/WN-i7.pdf Oscillators in a can is something I try to avoid. Too often I have seen that turn into a purchasing nightmare. -- Regards, Joerg http://www.analogconsultants.com
>>> >>>http://www.kvg-gmbh.de/ >>>http://www.quarztechnik.com/ >>>http://www.jauch.de/ >>> >>>Personally I am not a great fan of using crystals in environments that >>>shake a lot though. >>> >> >> You use a resonator, crystal oscillator or what? >> > > First I think really hard about whether the app really needs a precise > clock. Surprisingly often you can get away with ratiometric tricks and a > LC or even RC oscillator, or a trimmed internal clock like the MSP430F2xxx > family offers. Maybe Atmel has that feature as well. Rugged resonators is > the 2nd path but, of course, usually you still don't get crystal accuracy. >
When you have a CAN bus, I suspect you need good accuracy.
> http://www.avxcorp.com/docs/techinfo/WN-i7.pdf > > Oscillators in a can is something I try to avoid. Too often I have seen > that turn into a purchasing nightmare. > > --
-- Best Regards, Ulf Samuelsson This is intended to be my personal opinion which may, or may not be shared by my employer Atmel Nordic AB

Ulf Samuelsson wrote:


> When you have a CAN bus, I suspect you need good accuracy.
Not really. The tolerance as wide as 1% is good enough. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
Ulf Samuelsson wrote:

>>>>http://www.kvg-gmbh.de/ >>>>http://www.quarztechnik.com/ >>>>http://www.jauch.de/ >>>> >>>>Personally I am not a great fan of using crystals in environments that >>>>shake a lot though. >>>> >>> >>>You use a resonator, crystal oscillator or what? >>> >> >>First I think really hard about whether the app really needs a precise >>clock. Surprisingly often you can get away with ratiometric tricks and a >>LC or even RC oscillator, or a trimmed internal clock like the MSP430F2xxx >>family offers. Maybe Atmel has that feature as well. Rugged resonators is >>the 2nd path but, of course, usually you still don't get crystal accuracy. >> > > > When you have a CAN bus, I suspect you need good accuracy. >
Well, you hadn't mentioned CAN yet ;-) I am not familiar with CAN but on other buses it is possible to discard the first few transmissions and use these for synchronization. The first time we did that was actually on an Atmel 89LV51. Classical situation: It was in a separated interface that gets banged around a lot so I didn't want a crystal in there. Also, it had to be clock-silent for noise reasons when not in action (PCON) and after wake-up the oscillator wasn't particularly expedient in settling. More like a Harley on a cold morning. That meant we had no other choice but to synchronize to the data stream. Anyhow, sometimes I wish European car mfgs would occasionally take their new designs out into the wilderness here. Doesn't have to be as extreme as our "alternative road to Lake Tahoe" in the link below but I've had people turn pale and grab the dashboard. Including the occasional scream. On roads we'd consider "bad but kind of usable". http://www.rubicon-trail.com/ -- Regards, Joerg http://www.analogconsultants.com