ADR1399 reference

[iMo]

But why LT logo? Perhaps some legal stuff? Like patents, trade marks, IP, etc.? The Design remained mostly the same, afaik.

[DavidKo]

Mouser is shipping mine today. They still have 783 for dispatch today ;-)

[maat]

*knock* *knock* Oh, look what arrived today.

On the left and and right are samples I got earlier from ADI. These have a higher quality look than the production units (and also carry the ADI logo). It seems ADI tries to undercut the Ebay scammers selling refurbished diodes in terms of look and feel 

Off they go into the test setup. Lets see how they perform for the next 1 kh.

[analityk]

I've bought ADR1399KHZ and it arrived in weird ceramics package with standard that legs.
It is a bit curious because in datasheet was specified only ceramics smd package and metal can hermetically sealed to-42, but mine one is hybrid? I do not know, maybe someone here have any experience.
This ceramics shields act as heat insulation and inside is metal can?

[iMo]

Yep, that is the plastic heat insulating cap, inside is the metal package.

[Andreas]

Hello after removing the cap it should look like this:

and you get a thermal anemometer instead of a reference.
see patend of Joe Geller.

https://www.freepatentsonline.com/7380471.html
https://www.nutsvolts.com/?/magazine/article/micro_gust_thermal_anemometer_mgta

with best regards

Andreas

[iMo]

and you get a thermal anemometer instead of a reference.
see patend of Joe Geller.

Frankly, I doubt he could get the patent for that - as it is a known general principle, nothing new..
You may apply for such a patent with any similar heated device, like my old OCXO - the crystal frequency and heater current behave the same way.. 
PS: ..but perhaps no Einsteins sitting in the Patent Office anymore..
PPS: on the other hand we were laughing years back on a patent where the guy claimed uploading the binary into the mcu's flash via a bootloader, fortunately he indicated a single TI's mcu partnumber only.. 

[gamalot]

Hello after removing the cap it should look like this:

and you get a thermal anemometer instead of a reference.
see patend of Joe Geller.

https://www.freepatentsonline.com/7380471.html
https://www.nutsvolts.com/?/magazine/article/micro_gust_thermal_anemometer_mgta

with best regards

Andreas

Looks like they didn't change the structure of the thermal shield.

[BU508A]

Does not look like ADI's quality.. A fake?

On Feb. 2022 I've ordered 18 ADR1399KHZ directly from Analog Devices.
They arrived on 1st of August 2023.
https://www.eevblog.com/forum/chat/what-did-you-buy-today-post-your-latest-purchase!/msg4991827/#msg4991827



I have no idea, why they are using the LT logo and why the printing or engraving quality is so poor. I was surprised by myself when I saw it at first.

[iMo]

Details from my uscope..
It looks like laser engraving, but the intensity of the individual pulses differs.
Perhaps a code with a secret message 
PS: The intensity of the pulses could be constant, but the reflectivity of the surface might differ from place to place, therefore the mess.

[Andreas]

Hello,

update of ADR1399LS8 ageing 4kHr after putting into Hammond enclosure and with temperature compensation:
see also

https://www.eevblog.com/forum/metrology/adr1399-reference/msg4939813/#msg4939813


The ADR have now 7.3 kHrs in total operating time. Tempco is calculated out for the ageing curves.
The ADR1399LS8#01 - #03 are drifting slightly upwards ~2.5 ppm / 4 kHr in average over the last 4 kHrs.
The ADR1399LS8#04 has nearly no (<1 ppm) ageing drift.

with best regards

Andreas

[JodelJonny]

Hello,

this Saturday I used the offer of the PTB at the Maker Faire Hannover to get inofficial calibrations. I got some quick and dirty measurements of my 10V ADR1399 ref with a calibrated 3458A.  The measurements start quickly after I got the reference, that had already been powered on for a few hours with a battery, out of my backpack.

I just took pictures with my phone and used the timestamps to get a graph out of it. This is why there is inconsistent timing between measurements.
This was after approx. 3000h burn in time. 

I guess that the reference got relatively hot in the backpack and is cooling of during the measurement so that a negative tempco causes the rise in voltage.

 Thanks to the PTB team! I was nice to meet NNNI there as well.

[Andreas]

Hello,

my 2nd PCB is now populated additionally with 4 metal can devices. ADR1399KHZ.
Ageing drift for the first 2 weeks (333 hrs) starting after 1-2 hrs total operation time.
Unfortunately I have high changes in temperature in my lab between morning and evening.
So two measurements per day are not optimal.

Next I will check tempco of the 4 samples.

with best regards

Andreas

[Andreas]

Hello,

Tempco measurement on the 4 Metal can devices (KHZ) of 2nd PCB after 333 hrs run in phase.
I had hoped that the T.C. is lower than that of the LS8 packages.

But in comparison this is not the case. T.C. is very individual.

See also the (non pre-aged so with large drift) measurement of the LS8 packages..
https://www.eevblog.com/forum/metrology/adr1399-reference/msg4879958/#msg4879958

With best regards

Andreas

[iMo]

Interestingly the "red" noise decreases with the sample N..

[Andreas]

Not shure what you see.

But it could be that it is due to large changeing ramp speed (actual temperature differing from setpoint due to environment) during test.

with best regards

Andreas

[iMo]

Ok, your ppm scale on the right side differs..

[miro123]

Hallo,
I want to build few boards with ADR1399 and nomc/ot lt5400 resistor networks - are there any kicad/ altium reference design from other eebvlog members.
i need the design files since i want to do some modifications.  I have non-standard requirements
- ADR1399 & LM399 TO-46
- High stability 7V, 5V and 2v5,
- Something in 10....12V is nice to have.
- Small size is nice to have feature.
BR
Miro

[dietert1]

Not shure what you see.

But it could be that it is due to large changeing ramp speed (actual temperature differing from setpoint due to environment) during test.

with best regards

Andreas

One should be aware that a TC of 3 uV/°C is always in the range of thermal EMF. Those references run hot.
Maybe the residual TCs exhibit a pattern. If the numbering of references reflects their geometrical position on the test board, the apparent TC of the references follows a linear dependency - with one exception: ADR1399#2. Maybe it had some extra solder blob..

Regards, Dieter

[Andreas]

Hello,

news from the 2nd ADR1399 PCB:

See also
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5024692/#msg5024692

now I am measuring only 1 time per day (in the morning) so the temperature differences between measurements are smaller.

the 4 metal can devices have now 1kHrs. The values are now temperature compensated after having determined the T.C.

the 4 LS8 (SMD) devices have 100 hrs for initial measurements including T.C. measurement (not shown on the diagram) and after that 1 kHr temperature compensated ageing drift.

with best regards

Andreas

[Andreas]

Hello,

update of ADR1399LS8 on PCB#1 ageing 5kHr after putting into Hammond enclosure and with temperature compensation:
see also
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5011936/#msg5011936



The ADR have now 8.3 kHrs in total operating time. Tempco is calculated out for the ageing curves.
The ADR1399LS8#01 - #03 are drifting slightly upwards ~2-3.5 ppm / 5 kHr in average over the last 5 kHrs.
(now drifting in different directions).

The ADR1399LS8#04 has nearly no (~1.2 ppm) ageing drift.

with best regards

Andreas

[Andreas]

Hello,

update from the 2nd ADR1399 PCB now at 2 kHrs for the metal can devices (KHZ) and 2.1 kHrs for the LS8 devices (first 100 hours not shown):

See also
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5068999/#msg5068999

The values are all temperature compensated (temperature sensor at the bottom of the hammond die cast housing)

with best regards

Andreas

[branadic]

That is some interesting result Andreas. While the ADR1399KHZ seems to drift upwards (similar to what I observe for the Valhalla 2720GS/HSR-ADR and my ADR1399-PWM-DAC) all LS8 devices seem to follow the picture we can see in the datasheet.
This seems to indicate, that Figure 27 was achieved using LS8 devices, not TO-46.

-branadic-

[Andreas]

Hello branadic,

I have 2 PCBs with 4 LS8 devices each.
On PCB#1 all ageing drift is rising (datecode #2043)
here the drift is rising.
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5077309/#msg5077309
https://www.eevblog.com/forum/metrology/adr1399-reference/msg4308397/#msg4308397


On PCB#2 (see post above) I bought the devices much later
There I have falling drift for the LS8 devices. (unfortunately I did not write up the date code).

The metal can devices have date code #2316

I fear the direction of the drift is more related to the date code.

with best regards

Andreas

[Andreas]

Hello,

update of ADR1399LS8 on PCB#1 ageing 6kHr after putting into Hammond die cast enclosure and with temperature compensation (sensor on bottom of the hammond case)
see also
https://www.eevblog.com/forum/metrology/adr1399-reference/msg5077309/#msg5077309


The ADR1399LS8 have now 9.3 kHrs in total operating time. Tempco is calculated out for the ageing curves.
These LS8-devices are drifting upwards.

The voltage shift at the 2 LM399 (only for comparison) occurred after repair on the output connector. (while operating the cirquit).
Most probably I have damaged the Multiplexer for the "upper half" of the PCB during soldering.
(will have to check that when I have some time).

with best regards

Andreas