[volt-nuts] LTZ1000 project build

[Frank Stellmach]

This whole discussion does not really apply to the LTZ1000 circuit, that 
is the bare 7.15..V output, w/o step up amplifier, as all drift 
parameters were attenuated by orders of magnitude, depending on the 
resistors, R1-R5.

In the eevblog thread, several volt-nuts measured the real dependency, 
in contrast to the datsheet, which simply claims 1:100 attenuation for 
each of these resistors:


R1 	R2 	R3 	R4 	R5 	author
120 	70000 	70000 	12-15k 	1k 	
-1/770 	-1/250 	-1/1400 	+1/100 	
	janaf
-1/600 	-1/238 	-1/1000 	+1/87 	
	lars
-1/656 	
	
	
	
	TiN
1/714 	1/250 	1/3333 	1/105 	
	bbs38hot
-1/670 	-1/238 	-1/1184 	+1/74 	-1/75 	Andreas


Therefore, even humidity effects at most affect R4/R5, with 1/75 impact.

I also think, that it's possible for volt-nuts to measure such residual 
effects, by assembling several references, keeping the parameter of 
question (e.g. humidity or temperature) constant for the master 
reference, varying this paramater for a DUT, and evaluating the drift by 
monitoring the difference between the references.

Same goes for longterm drift, by using a group of many references (A man 
with one, two, three clocks..)

In the end, maintaining ultra precise references at first requires to 
care for controlled/constant ambient parameters, than to put too much 
effort to design references, which are immune to all possible drift factors.

Frank