Electronics > Metrology

Lowest drift, lowest noise voltage reference (ADR1000AHZ)

<< < (90/94) > >>

Dr. Frank:

--- Quote from: The Soulman on May 26, 2024, 01:09:02 pm ---
--- Quote from: Dr. Frank on May 26, 2024, 09:36:27 am ---Here's the drift update of the ADR1000's raw reference voltage.



After 2 1/2 years, it has stabilized to about -1ppm/year.
 
I made the power interruptions more visible in this graph.
I still have not measured / analysed, how much time it takes to reach the previous reference value, within 0.5ppm. 
Seems to be on the order of 2 weeks, depending on the off time.

Frank

--- End quote ---

Do you have a explanation for the long time ( 24+ hours ) it took to settle back close to its original value on 31-11-23?
Is the zener current circuit on your board somehow sensitive to moisture? Or the ADR1000 has a leak?  :-//
Or simply temperature related?

--- End quote ---

Obviously you do not understand what I have done .
The reference has been running since nearly 3 years now, but I switched it off three times, let it sitting idle for weeks, or for nearly 6 months last year.
I switched it on again December 1st.
The voltage simply had gone up 5ppm, or so, but recovered within 1 month to its recent value, to where it had been drifting, or ageing to the last 2 years.
These are obviously two relaxation process, and has nothing to do with humidity neither room temperature. The ADR is stuck into a test socket, not soldered.
Why should the package have a leak?
Both environmental parameters are absolutely constant in my lab, I.e always around 50% and 21.5°C.
I have not seen anybody else reporting this effect, but probably nobody else has done this test.
If this is a common characteristic of all ADR1000, this would inhibit a usage as a reference for DMMs.

The Soulman:

--- Quote from: Dr. Frank on May 26, 2024, 03:31:19 pm ---Obviously you do not understand what I have done .
The reference has been running since nearly 3 years now, but I switched it off three times, let it sitting idle for a weeks, or for nearly 6 months last year.
I switched it on again December 1st.
The voltage simply had gone up 5ppm, or so, but recovered within 1 month to its recent value, where it had been drifting, or ageing to the last 2 years.
These are obviously two relaxation process, and has nothing to do with humidity neither room temperature.
Both parameters are absolutely constant in my lab, I.e always around 50% and 21.5°C.
I have not seen anybody else reporting this effect.
If this is a common characteristic of all ADR1000, this would inhibit a usage as a reference for DMMs.

--- End quote ---

Yes I understand.
Just find it an odd and unexpected behavior.
Although your labs temperature and humidity levels are constant the (powered on) reference board temperature is above that room temperature,
combined with the thermal mass it may take a while (hours, days) to reach a final thermal equilibrium after switching on.
Also any component sensitive to humidity may absorb humidity when powered off and (slowly) dry-out when powered on.

I'm sure you know all this, just wanted to clarify myself.

I've seen this behavior before but only with v-ref's in plastic (dip) housings.

CalibrationGuy:

--- Quote from: Dr. Frank on May 26, 2024, 03:31:19 pm ---The reference has been running since nearly 3 years now, but I switched it off three times, let it sitting idle for weeks, or for nearly 6 months last year.
I switched it on again December 1st.
The voltage simply had gone up 5ppm, or so, but recovered within 1 month to its recent value, where it had been drifting, or ageing to the last 2 years.
These are obviously two relaxation process, and has nothing to do with humidity neither room temperature. The ADR is stuck into a test socket, not soldered.
Why should the package have a leak?
Both environmental parameters are absolutely constant in my lab, I.e always around 50% and 21.5°C.
I have not seen anybody else reporting this effect.
If this is a common characteristic of all ADR1000, this would inhibit a usage as a reference for DMMs.

--- End quote ---

If this is a common characteristic of the ADR1000, it would make it unusable in many calibration labs.

We had a conversation with the main tech and manager at Keysight's Standards Calibration Laboratory where the JVS is located, and they advised us to keep our meters running 24/7 powered by pure sinewave UPS backup units, which we do. We also have our 732 array on those backups.

Having said that, most other cal labs I know switch their meters off when not in use, rendering the ADR1000 unusable in reference meter applications.

Also concerning is the long stabilization time reported here. I have not personally tested it so cannot weigh in on the matter.

I hope this is not the case.

TomG.

Kleinstein:
At least the recovery after a turn off is relatively fast. So at least that process (e.g. stress between die and case or possibly redistribution of hunidity from silicon surface to case surface) is fast enough to be not a major issue for the long term stability.

For an application not running 24/7 this would be a major issue. If really a problem one could design the instrument in a way to keep the reference running with relatively low power and still power down most of the rest.

dietert1:
Yes, the time scale is typical for a humidity related process and it can happen inside the hermetic cavity.
The observed behaviour isn't that unusual. I have seen it with LTFLU references and on a LTZ1000, too. If you always turn on a precision voltmeter for a short period, you won't even notice, as the reference will remain close to the "off" condition.

Regards, Dieter

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod