[hpsdr] LTC 2208 A/D Thermal Characteristics

[Philip Covington]

On Wed, Jan 14, 2009 at 6:20 AM, Rob Frohne <frohro at wallawalla.edu> wrote:

> Most of the heat generated by the LTC2208 is transferred
> from the die through the bottom-side exposed pad. For
> good electrical and thermal performance, the exposed
> pad must be soldered to a large grounded pad on the PC
> board. It is critical that the exposed pad and all ground
> pins are connected to a ground plane of sufficient area
> with as many vias as possible.
>
> The interesting thing is that their example board didn't contain any vias to the ground plane that I could see anyway, so it seems that they didn't follow their own advice, or maybe I'm blind.  :-)

They are there.  There are very small vias on the demo board in the
thermal pad area.  The LVDS version even uses a special black solder
mask to help in radiating away the heat since the operating the
LTC2208 in LVDS mode generates the most heat.  I talked to Linear Tech
people extensively about heat dissipation when I was designing the
QS1R.

Phil N8VB

 1231947017.0