[volt-nuts] Some questions to zeners (1N823-1N829)
Andreas_-_Jahn at t-online.de
Sat Jan 26 10:30:34 EST 2013
after having experimented a lot with 5V monolithic zener references
and still not found the ideal solution I want to try a 1N82x based solution.
For me a extended room temperature range of
25 degrees centigrade +/- 7 degrees (64-90 °F) is of interest.
Since I plan to have battery supplied instruments a lower supply current would be of interest.
For the zeners a zero TC current is stated.
Over which temperature range the TC is nearly zero.
How large is the voltage deviation in the above mentioned range?
Does it play a role for the absolute temperature deviation if a 1N823 or a 1N829 is used?
Or is the behaviour equally when the individual zero TC current is used?
Is the only difference between the selections that the zero TC current is more near the 7.5mA value on the 1N829?
So is it more likely to get a low zero TC current of 4 mA on a 1N823 device than on the 1N829?
Or should I go for the 1N829A for the lowest absolute TC?
How large is the hysteresis on the zeners in a temperature range of 10-40 degrees celsius (50-104°F).
On monolithic unheated reference voltages with hermetic case I have up to around 2 ppm hysteresis difference
on temperature cycling. (see attached picture with 10-45 degrees celsius on X-Axis for an ADC with a 5V reference
measuring a LM399 heated reference over a 2:1 precision voltage divider. The ADC with the 5V reference is temperature cycled).
I blame the temperature hysteresis on the die attach to the lead frame which seems to be usually a silver filled epoxy compound.
I hope that the hysteresis on a discrete zener is much lower.
With best regards
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