ADR1001 - Ovenized Voltage Reference System

[EC8010]

I've just back-ordered an ADR1001 evaluation board from Mouser UK and been given a 30 July despatch date...

[Kleinstein]

The older high end zener references are in the 6.2 to 7.5 V and maybe 10 V range. This is OK for some uses, but needs extra effort to use with an ADC or DAC chip that wants 5 V at most.
With a 7 V ref and divider down to 5 V the divider can add quite some costs and drift. It is not a principle issue in designing a ref. circuit. The problem is more in getting suitable parts and valid specs for the long term drift part.

Chances are the long term drift depends on the set temperature for the chip. Another point is the mechincal design around the ADR1001.

[floobydust]

Pretty sure the fab is done in Taiwan, hermetic packaging in Philippines. Earthquake and dozens of aftershocks possibly adding a delay.
I will never forgive ADI for shutting down LT Hillview fab in Milpitas CA, which used to make our favorite ref IC's. Longtime proven quality. But it's sadly outsourced now and I would expect issues until the fab pulls it off.

[iMo]

Milpitas list..
I see there only two parts usually discussed here - LTC2057 and LTC665x..

[floobydust]

I remember the LTC Milpitas wafer fab change notice because it included LTFLU1A/SZ263 - which I thought were long obsolete.
It seems to have been wiped, I will keep digging see if I saved it. ADI is not saying a peep about it now.
Anyone know for sure where the LTC refs, including the new ADR1001 are being fab'd?

Other LTC parts i.e. PCN 19_0067 - June 2022 Product/Process Change Notice - 0.35 micron wafer fab from Hillview CA outsourced to Vanguard International Semiconductor Taiwan (subsidiary of TSMC). I suspect they are doing the ref fab.
Also hermetic packaging was outsourced, "22_0324 Feb-2021 ADI Philippines (ADPI) as an assembly plant to replace ADI Hillview for commercial hermetic products in TO5, TO39 and Sidebrazed Packages. {LTFLU1A, LTC1100-10, LTZ1000A}

My point is outsourcing advanced IC technology doesn't go well because the IC's are not yet commodities. It's a bean counter approach. You can't just play Lego with this stuff.
I imagine it's special fab process/lithography, a lot of specialty burn-in and test and manual labour involved- which is not mainstream.
I could be wrong and the production delays are something minor...

[EC8010]

I will never forgive ADI for shutting down LT Hillview fab in Milpitas CA,

I'll never forgive them buying Linear Technology and imposing the AD corporate model. I was told that LT people were very unhappy.

[floobydust]

This "fabless" semiconductor company model can never pull off state of the art. You are totally dependent on your contracted manufacturer.  Otherwise- you have your own people, your own facilities, like LTC, and it worked fine for them.
It is a huge loss for American semiconductor manufacturing in an era where Biden is throwing billions to onshore things.

Finer lithography 0.18u mentioned change "Analog Devices Beaverton OR, USA (ADBN) as an alternate Wafer Fab site to TSMC" I guess ADI has some token fab ability in America. Maxim was also hit with the acquisition and new stupid business model.

EEVblog could get their own voltage reference IC if outsourcing is so easy.

[bastl_r]

Finer lithography 0.18u mentioned change "Analog Devices Beaverton OR, USA (ADBN) as an alternate Wafer Fab site to TSMC" I guess ADI has some token fab ability in America. Maxim was also hit with the acquisition and new stupid business model.

This reminds me of my employer (automotive industry) where the management team consists almost exclusively of business people who believe that everything can be bought in the desired quality at the cheapest prices.
In addition, they overlook the fact that they are continually giving up core competencies that will never come back because the knowledge is gone over time and would have to be bought back at great expense.
Fortunately, I only have just under two years left...
But our children will suffer from these bad decisions!

[floobydust]

This ADR1001 seems to be quite late? About 19 months.
EDN April 10, 2024 "Voltage-Reference IC with Integral Heater Offers Single PPM-Class Results" they did a blurb about it but no mention of availability.

[nimish]

This ADR1001 seems to be quite late? About 19 months.
EDN April 10, 2024 "Voltage-Reference IC with Integral Heater Offers Single PPM-Class Results" they did a blurb about it but no mention of availability.

https://www.mouser.com/ProductDetail/Analog-Devices/ADR1001E-EBZ?qs=dbcCsuKDzFVDd32CmVL%252BIw%3D%3D

and https://www.mouser.com/ProductDetail/Analog-Devices/ADR1001AEZ?qs=ZcfC38r4PosJwibAPZPq6Q%3D%3D

expected June/July

Personally I'm more interested in where the hell their Silent Switcher 3's went.

[picburner]

If it's true they should arrive next week... or will it be smoke and mirrors?

[ITArchitect]

Christmas in May!  Good luck on your order and analysis!
 

[floobydust]

I notice they keep pushing back the delivery dates, repeatedly by a few weeks at a time. Need more mirrors or smoke.

[MegaVolt]

I notice they keep pushing back the delivery dates, repeatedly by a few weeks at a time. Need more mirrors or smoke.

If you look at the tests on this forum, there are obvious problems with long-term stability. It is noticeably worse than LTZ and SZA. And fixing this problem takes a lot of time. Perhaps some edits and reworking of the technical process.

[Noopy]

DigiKey has delivered my Christmas present! 

Datecode 2407 - Assuming the way to DigiKey wasn't too long one could guess that they use round about 14 weeks for aging/burn-in/whatever... Perhaps... 

[ITArchitect]

Ah, a true Christmas for a Volt Nut!  What's your heat up/analysis plan?  Will you be posting results?
Do you think the number is a date code or a serial/sequence number?

[Noopy]

"Don't turn it on, take it apart!" 
I have just a DMM6500. I can´t compete with the Volt Nuts here.
I´m curious whether they changed something in the two years between the engineering samples and the parts we can buy today. It seems they had some problems. Did they just tune the process or was it necessary to change something in the circuit?

Looking at the last ADR1001s we had, I´m pretty sure 2407 is the datecode.

[iMo]

I notice they keep pushing back the delivery dates, repeatedly by a few weeks at a time. Need more mirrors or smoke.

If you look at the tests on this forum, there are obvious problems with long-term stability. It is noticeably worse than LTZ and SZA. And fixing this problem takes a lot of time. Perhaps some edits and reworking of the technical process.

Where are the tests indicating the problems with the long term stability?

[MegaVolt]

Where are the tests indicating the problems with the long term stability?

Maybe this is my subjective opinion.
On many samples there is a constant drift which is very noticeable against the LTZ background

Here is an example comparison of ADR1000 and LTZ. And as I understand it, ADR1001 should have the same behavior or worse because... There is also an additional drift of internal resistors.

https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5378276/#msg5378276

[iMo]

Where are the tests indicating the problems with the long term stability?

Maybe this is my subjective opinion.
On many samples there is a constant drift which is very noticeable against the LTZ background

Here is an example comparison of ADR1000 and LTZ. And as I understand it, ADR1001 should have the same behavior or worse because... There is also an additional drift of internal resistors.

https://www.eevblog.com/forum/metrology/lowest-drift-lowest-noise-voltage-reference/msg5378276/#msg5378276

Hey, we talk here the ADR1001.. 

[MegaVolt]

Hey, we talk here the ADR1001.. 

I think the zener diode in ADR1000 and ADR1001 is made using the same technical process. And if they decide to correct something in the ADR1000, this will most likely affect the ADR1001. This is of course my guess

[iMo]

..Did they just tune the process or was it necessary to change something in the circuit?

The first thing I would check is the "1.7ohm buffer's output resistance issue"..

https://www.eevblog.com/forum/metrology/adr1001-ovenized-voltage-reference-system/msg4580656/#msg4580656

[Noopy]

Correct me if I´m wrong but we never found the 1,7Ohm on the silicon?

There is quite some (thin) wiring and some metal layer changes from BUF_F to the resistor divider. Is there someone with enough experience to estimate the resistance of this track?

[iMo]

I do not know where it comes from, but it is (or "was") real. That 1R7 "does not apply" when using the output buffer in 5V output mode, as it is within the opamp's loop (and the output resistance I measured is low, like 8m ). With 10V mode the 1R7 applies (it is off the loop). Perhaps they have made some change in the latest revision (if any revision at all, I somehow doubt).

[CalibrationGuy]

I see no availability of this part for months. Does anyone know of a source or know anything from the manufacturer?

TomG.