ADR1001 - Ovenized Voltage Reference System

[iMo]

..Hmm,
the T.C. curves are rather "discrete" (10 degree steps)
What I am fully missing is any specification for temperature hysteresis. (only switch off hysteresis which is rather large)..

The chip has been released to market, ADI writes.. So it is up to the voltnuts here to elaborate in very detail.. 
The hysteresis interpretation (in comparison to the LTZ/ADR1k designs) could be tricky with such a part as it is ovenized with all components (except the RISET resistor) on the chip. Unless it comes to the "thermal deregulation" it should show no hysteresis, I would say (provided the RISET has zero hysteresis).
Would be great to see some precise measurements here.

I plan to look at the output voltage of myADR#1 in the LAB2 this week, afterwards I would make again a change (out of my curiosity) - I would set the temperature to 40C (TSET wired to 6V6), add the RILIMIT into the heater and a Wima 100n between BUF_F and BUF_S. The chip temperature change will move the output voltage significantly.

As discussed here a year back my wiring of the 2x10k resistors to the TSET led to significant chip temperatures, for aprox 30-40 hours long, and that could be considered the annealing process after the soldering the package into my trampoline wiring, as the DS indicates, even though ADI "has not thoroughly
investigated the efficacy of this approach"..   

[iMo]

The RISET resistor characteristics are attenuated by a factor of 267 with respect to the 6.6 V reference output. That is, if the RISET value drifts by 10 ppm in the first 1000 hours of operation, that adds 10 ppm/267 = 0.003 ppm of drift to the 6.6 V reference.

I've been trying to decipher the RISET sensitivity out of the above info (DS rev0).
I reported (reply #84) roughly -300uV per ohm change (1/0.22*-60uV=-270uV), the LTSpice showed aprox -240uV per ohm change at the 10V output.

Say, the resistor is 110 Ohm, 10ppm drift means 10E-6*110=1.1mOhm change, that is 0.003E-6*6.6=20nV change.
So, 1ohm/1.1mOhm=909, and 909*20nV*10V/6.6V=28uV.
Hmm... 

Ah..
10ppm/267 = 0.037 ppm, it seems..
Then
0.037E-6*6.6=244nV
1ohm/1.1mOhm=909, and 909*244nV*10V/6.6V=336uV.
 

[iMo]

This is the LAB2 exercise from today.
Below the data I collected in the LAB2 - myADR1001# box spent 20h in the LAB2, then we made several short measurements, 10 readings averaged with SDEV, math done by the meters.
The shots will come later this evening
PS1: fyi - there is a 34401A measurement as well, after aprox 1h back at home.

[iMo]

And the summary of LAB A B measurements.
As the measurements are the matter of my hobby only - the results are a little bit hairy, with not consistent methodology, done under time stress, facing great meters with lot of buttons and cables picking up any airflow around.. 
Anyhow, it somehow follows the trend of my 34401A measurements.
The large step upwards comes from adding the foil feedback capacitor 4n7 to the OPA189 (also the two 1k resistors were added around the OPA189 in past with no measurable impact) as I reported several posts earlier (around +2ppm) here and here..
Below I've made a quick recap table with the data, while considering the calibration against FL732C (when done) and TC of the box (aprox -1.44uV/C).
All is preliminary and needs some further elaboration (if any..)

PS: My big thanks to the LAB A B owners who helped me kindly with these experiments!

[aronake]

https://www.analog.com/en/products/adr1001.html

now with pricing and order option on the Analog webpage.

1.000 pieces for 65.34 USD each
500 pieces for 76.29 USD each

Not sure if it is actually possible to order yet

[Noopy]

Hm, actually I wanted to post that here:

https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5315572/#msg5315572

 

[iMo]

The ADEV of the ADR1001 (the ADI's eval kit put into a metal enclosure) measured at PTB and presented by Luis during the "High performance digitizer and DC metrology meeting and mini workshop" in Bratislava today.

[Kleinstein]

For the shorter time scale the noise performance looks good. Still keep in mind that the 3458 also adds some (mainly white) noise from the protection and ADC, not just the reference noise.

For the longer time scale, like 10-100 seconds the ADR1001 noise does not look that impressive. Still a little better than the HP meter, but not much.  I would guess some thermal fluctuations near the heated reference to contribute.

[Okertime]

Does the graph show the ADEV of a 3458A while it measures the 5V of this specific ADR1001?

[MegaVolt]

Does the graph show the ADEV of a 3458A while it measures the 5V of this specific ADR1001?

What kind of magic allows you to keep zero in the region of pV with thermal EMF better than 10^-22?

[Kleinstein]

What kind of magic allows you to keep zero in the region of pV with thermal EMF better than 10^-22?

The magic step here is superconductivity. For superconductors the Seebecke coeffient is exactly zero and thus no thermal EMF as long as they are superconducting.

Does the graph show the ADEV of a 3458A while it measures the 5V of this specific ADR1001?

As far as I understood it, the graph for the 3458 is for measuring an essentially noise free 5 V from the JJA. The ADR1001 is measured as the difference to this same voltage.

[MegaVolt]

The magic step here is superconductivity. For superconductors the Seebecke coeffient is exactly zero and thus no thermal EMF as long as they are superconducting.

Is the Null detector also superconducting?

[Kleinstein]

In this case for the super low voltage test the null detector is also superconducting: a superconducting coil to produce a magnetic field and a squid magenetometer to measure the change in the field.

In this case the null detector is rather low impedance, just some µH of inductance and no real series resistance (though possible some loss to the inductance). The voltage is than calculated from U = L * dI/dt.

[MegaVolt]

In this case for the super low voltage test the null detector is also superconducting: a superconducting coil to produce a magnetic field and a squid magenetometer to measure the change in the field.

Thank you

Perhaps you have a document with a method for obtaining the figure 10^-22 V?

[mzzj]

The ADEV of the ADR1001 (the ADI's eval kit put into a metal enclosure) measured at PTB and presented by Luis during the "High performance digitizer and DC metrology meeting and mini workshop" in Bratislava today.

For anyone interested the whole presentation is available as PDF's over here:
https://indico.cern.ch/event/1357615/contributions/

[picburner]

I tried to order a pair of ARD1001AEZ via Mouser a few days ago and now that wording appeared in the order as per attached photo.
Issues in production?
Does anyone know anything about it?

[chuckb]

Digikey is listing a May 28 2024 shippment date

[picburner]

It says July 3rd to me.... and date approximate an subject to change.....
Will we talk about it again for 2025?

[Noopy]

I had a change from 27.3.2024 to 29.5.2024... 

Edit: Notice came 10.4.2024

[iMo]

@Noopy: you will regret deeply your decapping of perhaps the last ADR1001 chip produced.. 

PS: I wonder what would be the real reason behind - the production issues as indicated by Mouser, or ADI decided not to cannibalize their ADR1399 and ADR1000 sales, or the demand by the big players is extreme and the entire chip producion has been booked out for the next 10years, or ADI decided to stop the production because nobody wants it..

[chuckb]

Maybe they are adding a 1 month factory burn in!

[dietert1]

In case of urgent need there seem to be some for sale in Ireland. The title at ebay germany is "ADR1001 Ofengesteuerter, vergrabener Zener, Präzisionsspannungsreferenz".

[Noopy]

@Noopy: you will regret deeply your decapping of perhaps the last ADR1001 chip produced.. 

The less ADR1001 are sold the more valuable are also the pictures. 

In case of urgent need there seem to be some for sale in Ireland. The title at ebay germany is "ADR1001 Ofengesteuerter, vergrabener Zener, Präzisionsspannungsreferenz".

Interesting, these are no x-parts anymore... 

[iMo]

..vergrabener Zener..

..vergrabene Zaehne.. in this specific case..

[DimitriP]

or ADI decided to stop the production because nobody wants it..

One claims -0.5pm drift, the other -5ppm drift.

Yet the for the -5ppm drift part the datasheet uses these words:

"The on-chip heater, combined with Analog Devices buried Zener
technology, allows the ADR1001 to achieve sub-ppm temperature
coefficient performance and single-digit ppm long-term drift per-
formance. Besides providing best-in-class precision in all vectors,
the ADR1001 incorporates ease-of-use features to reduce cost and
design-in effort. "

If you didn't know about the 0.5ppm part, it all sounds good.

As for "reduce costs" and "design effort", it's not like precision voltage references came out for the first time last week and there is no design history,examples or experience out there...


I'm sure I must be missing something....why would a new part with more long term drift be preferable?