[SI-LIST] Re: PCB in plastic enclosure
- From: Ihsan Erdin <erdinih@xxxxxxxxx>
- To: sunil_bharadwaz@xxxxxxxxx
- Date: Fri, 30 Nov 2012 20:00:03 -0500
Sunil,
With a 10cm2 plane and 75uA current, I wouldn't even bother about the
thermal issues on that card. But if you want precision you should
characterize the dc current on the card first. Sigrity and SIwave are the
two tools that can do that. There are probably others, too, but those two
are the ones familiar to me. Once you get the current distribution and
power density on the metal structure you can derive the thermal profile of
the card with simple circuit equations after mapping thermal parameters to
equivalent circuit parameters. For the overall system evaluation, you can
feed the power density data to a dedicated thermal simulator (flotherm,
icepack, etc.) and get the results.
Regards
Ihsan
On Fri, Nov 30, 2012 at 10:06 AM, sunil bharadwaz <sunil_bharadwaz@xxxxxxxxx
> wrote:
> Hi All ,
> We have designed a battery operated wireless system placed in a plastic
> casing.
> The PCB has a battery & other electronic components . It continuously
> draws about
> 30 uA ( sleep current ) .The Tx gets switched ON at a relatively low
> duty cycle ,
> where in the total average current becomes about 75 uA.The PCb has a
> ground
> plane of 10 sq cms.Battery is at 3.0 V.
>
>
> The board is enclosed in a plastic casing , which is thermally insulated .
>
> Considering that the battery would last for say an year or two - does the
> temperature of the PCB , increase continuously ?How do we ensure
>
> that the temp stays with in limits .
>
>
> What tools are required for such an analysis . Pls point me to any
> relevant
> links .I did try to do some homework - but not much luck so far.
>
> Any info in this regards would be highly appreciated .Thanks to you
> all in advance .
>
> Best Regards
> Sunil.Bh
>
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--
Ihsan Erdin
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