Increasing Sensitivity (was Re: [MLB-WIRELESS] <PLUG> Cheap prices for wireless gear)

[John Dalton]

> Cooling down the PA and LNA will actually make matters worse;

It's not that simple.


> Most of these ICs are rated from around 0-85 degrees. 
> 
> Look at some of the datasheets from Intersil & RFMD

This is simply an ambient temperature range over which
a set of specifications are guaranteed.  It doesn't
necessarily relate back to correct device operation.
They are not a hard numbers.

The upper temperature is set by the necessity to keep
the junction temperature (ie. the temperature of the
actual silicon) of the circuits transistors below
about 150C.  Above this temperature the transistors
break down and cease to work.

The lower temperature is usually set for mechanical
reasons, not electrical.  As the temperature drops,
differing coefficients of thermal expansion cause
bits of the circuit to move relative to each other. 
This can result in a cracked die, broken connections,
and so on, inside the package.

You can generally push chips below their lower
temperature limit provided the rate of temperature
change is well controlled.  Of course if it falls
apart, the manufacturer will say 'told you so'.