I forgot where I read it [maybe in the LTZ's datasheet?], but Linear-Tech recommends 1mm spacing between the bottom of the TO99 package and the PC board.
Hello,
I could not find this in the LTZ datasheet.
Has anyone a hint where this info can be found?
But if I think about it then I did a error when shortening the pins of LTZ#4 to zero.
On the other side the T.C. on #4 was very widely off without this measure.
This cathode resistor should be very stable [Edwin's PWW with stabilization or VPG foil with PMO].
That is not my way of adjusting the T.C. You need a additional very stable component. (and my PCB layout is not prepared for this).
And finally the copper traces on the layout determine a large amount of the T.C. of that additional component.
In a small range I can adjust the T.C. by populating R9 (which is already in Layout). And here I can use a standard 1% metal film resistor.
For a working point of 50-55 deg C the compensation is around +0.04 ppm/K for each 1 Meg resistor.
That's entirely up to to your requirement.
I think it was more or less a rhetorical question. As a volt nut I have at least to try it.
The 10 V output is still far away.
I think I will have to use a DAC and a NTC to compensate for the temperature changes
in order not to worse the 0.05 ppm/K spec of the reference.
With best regards
Andreas