$5 AD584 voltage references - Page 1
Forum section: electronics / testgear

author: ralphd
author_rank: Frequent Contributor
timestamp: November 11, 2015, 02:45:01 pm
content: http://www.aliexpress.com/item/AD584-2-5V-5V-7-5V-10V-High-Precision-Voltage-4-Channel-Reference-Module/32521304265.htmlGiven the price, I imagine these are AD584Js. Looking at the datasheet, the 5ppm vs 3ppm/C looks like the only relevant difference. Noise, drift, line & load regulation are all the same.http://www.analog.com/media/en/technical-documentation/data-sheets/AD584.pdfI'm looking for something to test my 6000 count DMM. The AD584 module voltages are measured with an Agilent 34401 (I've seen the calibration labels posted by some other vendors). While I doubt the 34401's used to calibrate these modules are calibrated annually (for 35ppm accuracy), even if the reference voltages are accurate to 70ppm that would be fine with me.

author: Fungus
author_rank: Super Contributor
timestamp: November 11, 2015, 02:55:13 pm
content: If you're only going to buy one, it might be a good idea to pay a teeny bit more and get it from a decent supplier.

author: c4757p
author_rank: Super Contributor
timestamp: November 11, 2015, 03:06:21 pm
content: Quote from: Fungus on November 11, 2015, 02:55:13 pmYes, this. One from a reputable supplier is only $3 more.

author: Fungus
author_rank: Super Contributor
timestamp: November 11, 2015, 03:14:56 pm
content: Quote from: c4757p on November 11, 2015, 03:06:21 pmOr ask AD for a free sample. You never know...

author: bigsky
author_rank: Regular Contributor
timestamp: November 11, 2015, 03:37:49 pm
content: I have one of the Chinese voltage reference modules made with an AD584 in a small Perspex case with Li-ion battery etc. There's been various discussions about them here. The label on it with the voltages says they were measured with a 34401 and I reckon they are accurate as they agree with my various Flukes to within a couple of counts. I'd guess they sell for around US $20 and are very convenient.

author: ralphd
author_rank: Frequent Contributor
timestamp: November 11, 2015, 03:46:41 pm
content: Quote from: c4757p on November 11, 2015, 03:06:21 pmWho do you recommend (note that I don't do ebay)?

author: c4757p
author_rank: Super Contributor
timestamp: November 11, 2015, 03:48:38 pm
content: DigiKey?

author: ralphd
author_rank: Frequent Contributor
timestamp: November 11, 2015, 04:00:51 pm
content: Found a 584K module for ~$6 during the 11/11 sale:http://www.aliexpress.com/item/AD584kH-4-Channel-2-5V-7-5V-5V-10V-High-Precision-Voltage-Reference-Module/32387122637.htmlOne of the reviews is from a buyer that tested it against a keithley 2001, and found it accurate to under 1mV. I think I'll go for this one.

author: krivx
author_rank: Frequent Contributor
timestamp: November 11, 2015, 04:05:50 pm
content: Is there any reason you'll use Aliexpress and not eBay? For things like this they are often the same sellers on both sites. I think your odds of getting something counterfeit are about the same

author: ralphd
author_rank: Frequent Contributor
timestamp: November 11, 2015, 04:13:42 pm
content: Quote from: krivx on November 11, 2015, 04:05:50 pmMany sellers on eBay do paypal only, and after dealing with paypal's horrid customer service, I'll never use it again.All AliExpress orders are escrow, so the seller doesn't get their money until the order is confirmed received. While the AliExpress dispute resolution is poor, I use a credit card for all purchases and will do a merchant chargeback if I don't get a refund through AliExpress.

author: eas
author_rank: Frequent Contributor
timestamp: November 11, 2015, 07:10:47 pm
content: I have one like this:http://www.aliexpress.com/item/AD584-High-Precision-Voltage-Reference-Module-4-Channel-2-5v-7-5v-5v-10v/32346545467.htmlThe provided "cal" values for 2.5, 5, 7.5 and 10v are 9, 8, 27 and 51 counts lower than the values I measure int he 10v range with my HP34011a, which was last calibrated in 2010, according to the sticker on it when I bought it. I'm measuring at 4°C below the temp reported with the provided values. I'm powering the module off a linear supply.For what it is worth.Quote from: c4757p on November 11, 2015, 03:48:38 pmDatasheet spec for initial accuracy is 0.3%, or 30mv at 10v.