Calibratory D-105 DC Precision Voltage Reference Standard - Page 1
Forum section: electronics / general

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 31, 2015, 12:41:38 am
content: Looking to add to my collection of Standards devices, I ran across this seller on eBay who appears to make a decent 10VDC reference standard. The unit is small and compact and the specifications are impressive for the $100 dollar price tag it carries. It supplies 10.000000 VDC Output with ±0.0002% (±2ppm) at 14.5VDC (+-2.0VDC) on the input. The unit can operate anywhere from 12VDC to 35VDC on the input. The unit incorporates a TI REF102C reference IC, Noise Filtering, Thermoelectric Dampening and more. They have taken into account silicon aging, high granularity trimming, output jitter dampening, resistive balance, temperature compensation and more.The device has a 5-minute settle time and the max output load is 10mA, Long-term drift is <1.5ppm/1,000 hours of use decreasing with age. I have ordered one and will let you know what I think once I get it. I thought others might also be interested in this unit also so here is the eBay link:http://www.ebay.com/itm/10-VDC-2ppm-Precision-Voltage-Reference-Standard-Nulled-to-Fluke-732A-or-732B-/251756273626?

author: quarks
author_rank: Frequent Contributor
timestamp: January 31, 2015, 08:05:29 am
content: Thanks for sharing.Sounds good, but I wonder if it really performs as advertised.AFAIK the REF102 comes in plastic package, gives 10V +- 2,5mV output, has 2.5ppm/K at best.Therefore it needs to be trimmed and use very clever correction/compensation to meet the claimed numbers.Looking forward to what you find out.Byequarks

author: saturation
author_rank: Super Contributor
timestamp: January 31, 2015, 03:21:25 pm
content: Very very interesting, but I find the specs hard to believe. Creating a reference with such specs at low cost is the holy grail of the voltnut and naturally it wouldn't hurt pros either too. Would be very interested in your report and tear down.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 31, 2015, 04:06:47 pm
content: I agree, the specs seem hard to believe but I am willing to give it a go and see if it meets their claims. I can easily measure and test it out to 6 digits or more if needed. I want to see how stable it is over a week, month even longer. Although I won't wait that long to post my review!

author: theatrus
author_rank: Frequent Contributor
timestamp: January 31, 2015, 05:38:21 pm
content: Tearsdowns appreciated.I'd pick one up and run it on my 3458a but I'm just slammed on time.

author: saturation
author_rank: Super Contributor
timestamp: January 31, 2015, 06:08:48 pm
content: Yes, don't keep us in suspense for long. I'm surprised I never heard of any of this product or variants at volt nuts but now that you've made us aware via eeblog, many other pioneers may join the adventure.Quote from: Terabyte2007 on January 31, 2015, 04:06:47 pm

author: jimon
author_rank: Regular Contributor
timestamp: January 31, 2015, 06:17:20 pm
content: Wish to have teardown.

author: dom0
author_rank: Super Contributor
timestamp: January 31, 2015, 06:46:33 pm
content: +- 2 ppmabsolute accuracysounds extremely unlikely, both due to the price and the reference used.

author: devanno
author_rank: Regular Contributor
timestamp: January 31, 2015, 07:19:22 pm
content: I saw this on eBay a while back and thought ... hmmm at this price? Really interested in your experiences. Thanks!

author: dadler
author_rank: Unknown
timestamp: January 31, 2015, 07:53:56 pm
content: Seems that for such a precision product, I would choose a more professional outlet than eBay to peddle my wares, but what do I know. Someone get one and test it for us.

author: jpb
author_rank: Super Contributor
timestamp: January 31, 2015, 07:54:44 pm
content: Wasn't there a thread on this a year or so back? I remember the references to "Nulling" and using a Fluke to do so.I did a quick search and couldn't find it but my memory is that there was a degree of snake oil involved.

author: jpb
author_rank: Super Contributor
timestamp: January 31, 2015, 08:08:47 pm
content: I've found the reference, on page 51 of the massive Ultra Precision Reference LTZ1000 thread :https://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/750/it is the same ebay seller. It might be worth re-reading the earlier comments.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 31, 2015, 08:42:16 pm
content: Quote from: jpb on January 31, 2015, 08:08:47 pmThis ought to be very interesting then. I am going to hold the seller to his claims so if it fails the tests it will be published here on the EEVBlog and elsewhere. I will only use up to date calibrated and traceable equipment, just in case I get called out on that later. More to come...

author: Dr. Frank
author_rank: Super Contributor
timestamp: January 31, 2015, 09:14:40 pm
content: 100$ ... Give it a try.. If you're able to verify it.Personally, I doubt the performance , once from the capabilities of these refs, 2nd because the description is too enthusiastic, and there's a strange list of compensation features... Like these guys, which claimed supercaps from nanoparticles, and Free Energy, and so on.You know, they all simply use common terminus technicus / pseudo scientific terms in such descriptions , without really being able to implement these...At least, if this community would be able to prove this gadget to not fulfill the claimed specs, you may blame him afterwards.I also offer to check this circuit to ppm uncertainty.Frank

author: EEVblog
author_rank: Unknown
timestamp: January 31, 2015, 09:23:47 pm
content: Quote from: dom0 on January 31, 2015, 06:46:33 pmYes. All these would have to be extensively hand characterised and aged to guarantee this spec. Don't know how that can be done for the money.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 31, 2015, 09:34:39 pm
content: Quote from: Dr. Frank on January 31, 2015, 09:14:40 pmI can't disagree with your post. Yes, there are many claims out there on eBay and elsewhere that are most likely exaggerated but for $100 bucks I think it's worth a look. I will follow up with all my data once I receive and do the testing. If there are any other suggestions, please feel free to let me know. I want to be as thorough as possible.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: January 31, 2015, 09:38:17 pm
content: Quote from: EEVblog on January 31, 2015, 09:23:47 pmDave, maybe I can buy another and donate it to the EEVBlog for you to tear into it! Don't you have an HP 8 1/2?

author: EEVblog
author_rank: Unknown
timestamp: January 31, 2015, 09:53:27 pm
content: Quote from: Terabyte2007 on January 31, 2015, 09:38:17 pmNo, I'd have to test such a thing at the local cal lab.And of course it would have to be tested over temperature, and I'm not sure they have the ability to do that, so I'd have to take my thermal oven. It's a lot of work to test such a thing properly. I doubt they'd let me tie up their lab for a few days to do this.Best I can do in the lab is keep the lab temp without about 0.5C with a 34461A meter which is 6ppm rated drift, so maybe 3ppm drift at best according to datasheet specs. I'd be down in the noise.

author: Andreas
author_rank: Super Contributor
timestamp: February 01, 2015, 07:33:39 pm
content: Quote from: Dr. Frank on January 31, 2015, 09:14:40 pmHello,I also doubt that this performance (+/- 2ppm) is possible in a plastic package.The better value of long term stability (5ppm/kHr) is usually only for the metal can package (TO-99) which is now marked as obsolete. For the plastic package 20 ppm/kHr are specced. The "typical" 5ppm/kHr of the foot note after 168hrs are usually only valid for lab conditions with constant humidity. In real life applications the plastic packages will drift with humidity.Further all accuracy specs in the datasheet are additive. So a good performance is only possible under very stable conditions.If you let the power supply at +/-2V accuracy the +/-2 ppm are already used up by the PSRR of 1ppm/V. And that parameter is meant without self heating due to changing power consumption.If you really draw 10mA the 10ppm/mA will sum up to 100ppm. (+additional drift due to self heating)."No soldering" (= socket for the REF102) sounds good for the first. But over time when contact oxidation takes place you might get strange effects by a socket.There is no statement about pre-aging for the D-105 DC.In my opinion at least 1 kHr continuous operation would be necessary before first calibration.So all in all:Although the REF102 is a excellent reference (in TO-99 package)in the plastic package I would not expect to get better than 10-20ppm over 1 year with following measures.- well stabilized power supply around 15V.- no load on the reference output- temperature controlled operationA better choice for a reference would be the AD587 in CERDIP package.In my ageing experiment I am running one REF102AP against several AD586LQ (5V) references.14V stabilized power. 50 deg C stabilized temperature. No Load at reference.Within first 70 days ageing drift was 10 ppm and seems now to stabilize.When regarding stability the plastic package is far not so stable than the CERDIP devices.With best regardsAndreas

author: HighVoltage
author_rank: Super Contributor
timestamp: February 01, 2015, 10:13:51 pm
content: I noticed this one before but expected it to be a cheap wannabe standard.Since I have the aged Geller Labs SVR-T, it might be interesting to compare the two.I just wanted to order one, but it seems the seller is not sending to Germany.

author: HighVoltage
author_rank: Super Contributor
timestamp: February 02, 2015, 01:44:24 pm
content: I just ordered one unit and asked a few questions and this was the answer:Quote:The reference ICs are burned in for ~1,000 hours prior to use. But that is to produce good "long-term" stability. The +-2ppm figure is the maximum error. To get that we use temperature-compensation. It took about three years to develop the device. I have a scientific background. So, I only had to learn the application side.It's basically just inspiration + education + resource + experience + planning + trial and error + persistence + good equipment + common sense + hard work + prayer = good results. It's not a nuts and bolts kind of explanation I can give, because each unit is custom made. These items cannot be mass-produced. And that's part of the secret! The Fluke 732A is like that. They were all handmade.Magic is science not yet understood. There is so much innovation in this product that it appears to be magic. But it does work as specified. I hope you can understand that our device is protected by trade-secret in construction and calibration. Therefore, I cannot reveal everything about the device.Thank you for your inquiry, and for your purchase.End-QuoteWell, we will see how good it is, when it arrives.

author: Terabyte2007
author_rank: Frequent Contributor
timestamp: February 02, 2015, 02:58:10 pm
content: Quote from: HighVoltage on February 02, 2015, 01:44:24 pmMine should arrive in the next day or two. The reply sounds sincere but a bit odd. "Magic is Science not yet understood???" I will post my findings once I get the unit and run some tests...

author: dom0
author_rank: Super Contributor
timestamp: February 02, 2015, 03:03:05 pm
content: The reply of the seller, while long, contains little information except for the usual feeble "I have been doing this for X years, I don't have to explain to you, because I know what I'm doing" argument.

author: retrolefty
author_rank: Super Contributor
timestamp: February 02, 2015, 03:40:29 pm
content: Quote from: dom0 on February 02, 2015, 03:03:05 pmI'm not so sure. He seems to be pretty open and straight forward to me. His claims for his product should be pretty simple to judge just on facts obtained from direct observation.I say most reasonable tec types would just wait for the promised results rather then pretty subjective speculation about the product?

author: dom0
author_rank: Super Contributor
timestamp: February 02, 2015, 03:56:27 pm
content: That is correct, however, my post related mostly to the lower 70 % of the sellers answer.