Electronics > Metrology

ADR1399 reference

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Andreas:
Hello,

update from ADR1399 PCB#2 now at 5.4 kHrs for the metal can devices (KHZ) and 5.5 kHrs for the LS8 devices (first 100 hours not shown):

See also
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5303665/#msg5303665

I have exchanged the MAX4052A multiplexers against standard HEF4052 (NXP) CMOS devices.
As result ther is a relative large jump on all references.
But also the "ageing" slope has changed significantly on all channels (mostly near zero).

So I fear that up to now I have measured the "ageing" of the MAX4052A instead of the references.
That also would explain the difficulties with my "position dependant drift".
I think that the MAX4052A are not usable for higher supply voltages than ~10-12V since I never recognized something unusual with 5V.

Should have used a relay multiplexer instead?
In the mean time I also have some DG4052 to give them a try.

with best regards

Andreas

CalibrationGuy:

--- Quote from: Mickle T. on February 15, 2024, 01:34:29 pm ---A simple, general-purpose, dual-voltage (10V and 1V) reference based on the ADR1399 in a TO-46 package. Temperature coefficient <0.2 ppm/°C (10 V), noise amplitude 0.25 ppm p-p (0.1-10 Hz). Resistors are selected with TCR 0.2...2 ppm/°C.

https://youtu.be/guZnwp_DdUM

--- End quote ---

This is a beautifully executed project. How long did this simple project take? How much did it cost you when all is said and done? Anyway, thanks for sharing.

PS - It costs my lab over $2700 per 3458A to backup our numbers. Voltage tests here are a bit subjective because even a Keysight ISO17025 calibration has an uncertainty of 1.1ppm.

ivo:
I wonder if anyone with capable equipment, would be interested in testing if there's any appreciable difference in noise, and tempco ppm sweeps, over different reference currents? Say 3mA/6mA/10mA?

CalibrationGuy:

--- Quote from: ivo on April 03, 2024, 04:14:20 pm ---I wonder if anyone with capable equipment, would be interested in testing if there's any appreciable difference in noise, and tempco ppm sweeps, over different reference currents? Say 3mA/6mA/10mA?

--- End quote ---

If such a request were made, you would have to clearly define what tests you would want including tolerance, number of samples, test conditions, etc. People who have labs are usually busy people. *cough* *cough*

TomG.

iMo:

--- Quote from: ivo on April 03, 2024, 04:14:20 pm ---I wonder if anyone with capable equipment, would be interested in testing if there's any appreciable difference in noise, and tempco ppm sweeps, over different reference currents? Say 3mA/6mA/10mA?

--- End quote ---

The "zener current" inside the 1399 is set to a specific "constant value" by ADI, the same as with 399 (the chip is almost the same). You cannot change that current from outside.

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