[sdiy] SSM2164 last time buys

[David G. Dixon]

> Yes the current source solution suggested by Steve works.
> 
> I used the LM334 (10mA) because it is what I had at hand but it would be
> better something like 15mA or 20mA.
> Yes I connected the (+) to the positive rail, and (-) to the pin 16 of the
> 2164. And a 7Ω resistor from (-) to the centre leg(r)

Here's what H&H has to say about the LM334 (2nd ed., Section 16.18, p. 355):

"National makes a special 3-terminal device, the LM334, optimized for use as
a low-power current source.  It comes in the small plastic transistor
package (TO-92), as well as the standard DIP IC package.  You can use it all
the way down to 1uA, because the "adj" current is a small fraction of the
total current.  It has one peculiarity, however: The output current is
temperature-dependent, in fact, precisely proportional to absolute
temperature.  So although it is not the world's most stable current source,
you can use it (Section 15.01) as a temperature sensor!"

Hmm.  Based on that, I'm wondering whether a simple resistor might not be
the better choice for temperature stability.