[volt-nuts] Best reference after LTZ1000

Andrea Baldoni erm191ba3 at ermione.com
Mon Aug 16 23:29:18 UTC 2010

On Sun, Aug 15, 2010 at 01:56:03PM -0700, Dick Moore wrote:

> The 34401 uses a reference from the National LM199 family -- I suspect
> they're selected in some first-order way to keep costs down. So using a few
> LM399's, each with a little series resistance in parallel driving a
> stable op-amp like an LT1150 chopper amp might be the best way to go. In my
> experience, the LM399 aging curve tends to flatten out significantly after
> about 10 hours of run time, so it doesn't take too long to get them pretty
> stable, and then using two or three or four is cost effective and tends to
> make a more stable system.

Do you think that controlling the temperature of LM399 by sensing his case
and using a PWM (or linear) control over the heater might improve his stability?
After all (ok, not quite) it's like to have an LTZ1000 that way...
The cost would be _very_ different hovever and you may make batteries of 4
as you wrote.

Another thing to try at home. 

Best regards,
Andrea Baldoni

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