[hpsdr] LTC 2208 A/D Thermal Characteristics

[Philip Covington]

On Wed, Jan 14, 2009 at 12:31 AM, Scott Cowling <scotty at tonks.com> wrote:

> That means the junction temperature, T(j), will be only about 1/3 of a
> degree higher than whatever temperature you measure on the case.

I agree with Rob that this analysis is flawed.  There is no way that
the junction temperature is only 0.33 C higher than the temperature
measure at the top of the LTC2208 package.  If people are measuring 70
C at the top of the chip then the junction temperature is considerably
higher.

> Could we make it cooler? Sure we could. Do you want to add noise by hooking
> up a BIG ground plane to the pad on the underside of the chip?

This is exactly what Linear Tech suggests because this is the only way
to get the heat out through the thermal pad on the LTC2208.   The
notion that somehow this would increase noise is nonsense.

Phil N8VB

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