[volt-nuts] Zener, IC, references - which one

Andrea Baldoni erm191ba3 at ermione.com
Fri Feb 13 08:31:24 EST 2015

Hello All.

I would like to experiment with voltage references by putting them into a
ovenized chamber (a DOCXO with a broken crystal) with their bias and buffer
circuitry. The final goal will be to have the way to calibrate the HP 34401 as
well as other instruments, but now I want more to "learn by doing".

The chamber has his own heater so I'm not planning to use LTZ1000 or LM399
unless I leave their internal one unconnected.

Between the ones I am able to find new on the market, there are the zener
diodes 1N829A (6 EUR new, 8 EUR NOS), the LM399H (12 EUR), the LM329BZ (4 EUR),
while the LTZ1000 and the SZA263 are available used.

I'm more concerned with long term stability than TC because everything will lie
in a very constant temperature oven; I would like to use more expensive devices
only if they have some advantage (IE, the LTZ1000 is really better than 1N829A
or the advantage come by the fact it has his own oven?).
Also, about external circuitry, what op amp do you suggest? A chopper one is
probably not needed, always because it lies in a oven, and it may add noise.
And about resistors? Yes, there are Vishay Z-foil, but there are other with
worse tempco but same long term stability?

Best regards,
Andrea Baldoni

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