Author Topic: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x  (Read 154727 times)

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Offline 42Khz

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #625 on: June 01, 2019, 02:42:18 pm »
Recently i bought 10 pcs 2DW232 from aliexpress.
Can anyone suggest me a simple method to test if them are originals or fake?
I have only 2 Multimeter (UT61E + AN850B), 1 Power Suply KA3005D and a Rigol DS2072A.

The easiest way is to crack one open.
If it's a single die inside covered in some gunk it's probably real (I'm not aware of any fakes like that) and if it's two discrete zeners it's a fake.
 

Offline Kleinstein

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #626 on: June 01, 2019, 03:59:02 pm »
Looking inside is probably the easiest way.
A non destructive way would be to build a simple reference circuit and measure the noise. Chances are high the fake ones would be much higher noise. I would not mind "fakes" that are very low noise.
 

Offline stijena1973

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #627 on: September 02, 2019, 12:13:29 pm »
I suspect that the component is fake. BE junction of some si transistors in the opposite direction behaves as 5.6 V zener. Could it be a mislabeled transistor?

Check for hfe, just in case.
 

Online sorin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #628 on: September 02, 2019, 01:04:38 pm »
They are not  transistors.
 

Offline cape zoloh

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #629 on: September 20, 2020, 09:05:25 pm »
Sorry to bump this thread. If anyone got some of the 2DW233/2 (with the diamond mark) for sale (or trade), please send me a message!
« Last Edit: September 20, 2020, 09:11:47 pm by cape zoloh »
 

Offline MegaVolt

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #630 on: September 21, 2020, 12:44:58 pm »
Sorry to bump this thread. If anyone got some of the 2DW233/2 (with the diamond mark) for sale (or trade), please send me a message!
I bought here. There is a diamond sign.
Didn't check the parameters :(
https://aliexpress.ru/item/32871103478.html
 

Offline Pipelie

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #631 on: September 22, 2020, 06:58:51 am »
Sorry to bump this thread. If anyone got some of the 2DW233/2 (with the diamond mark) for sale (or trade), please send me a message!
I bought here. There is a diamond sign.
Didn't check the parameters :(
https://aliexpress.ru/item/32871103478.html

be ware that not all the 2DW232 with diamond mark is the low noise one. we have tested samples from several source and we found the date code start with 12-xx and 13-xx are most likely the low noise one. the newer one is probably not, such as the 14-xx to 15-xx we tested are kind of bad.
 
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Offline KK6IL

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #632 on: October 17, 2020, 04:58:18 am »

I ordered 20 from the address MegaVolt supplied, and received 2 packages of 20 each, date code 15-4 (and 2 credit card charges). I may or may not have double ordered, not being used to AliExpress. Inked markings not very distinct.

With Pipelie's warning, I wanted a quick noise test so set up a comparison with a LM329. I set up a test using my LM399 standard as the source, 3K resistor for the LM329, and 750 ohms for the 2DW323, pins 1 & 2. Measured with Tek 7A22 plug-in set to 1Hz-1kHz bandwidth. Photos captured with Hantek DSO connected to 7834 Vertical Output. LM322 voltage source measures 35.6uV P-P. LM329 measures 25.2uV P-P, and 2DW232 measures 5.2uV P-P.

 
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Offline Andreas

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #633 on: October 17, 2020, 02:15:46 pm »
Hello,

so you have 1:50000 amplification?

Hmm, to measure 1Hz you would need a minimum sweep time of 1 second.
Otherwise you get another pole by the limited measurement duration.

with best regards

Andreas
 
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Offline KK6IL

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #634 on: October 17, 2020, 11:43:39 pm »
You're correct. The high pass filter on the 7A22 plug-in ( love those) was set to 1 Hz, but the sweep time would have to be set slow to actually show really low freq noise.

I was just glad to see that the 2DW232's from that site were real Diamond components and were low noise compared to the LM329's.

I built a copy of a "low noise" 60 db amp, and was trying to add that to the test setup to get further above the scope noise when my LM399 supply started latching into a 3.5V output mode,  |O so will need to build a low noise, higher current supply to do further testing. The DW will be good for that as I will only worry about short term stability, and not 0 TC.
 

Offline Kleinstein

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #635 on: October 18, 2020, 09:28:31 am »
Chances are that even the not so good 2DW232 would be OK at the higher frequency. The real test is for the low frequency range and 1/f noise. The 1/f noise is what depends one purity and can vary between batches.

For a simple noise test one would ideally have to independent references and than measure the difference.
There is no real need to have a separate low noise supply. The normal 1 OP amplification of the ref. and getting the current from the amplified voltage should be Ok. This may even work with an LM358 on a breadboard - though poor contacts can be a hassle.
The difficulty may be more in setting the right current as 1/f noise and temperature fluctuations can look similar.
 

Offline edavid

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #636 on: October 19, 2020, 03:46:51 pm »
be ware that not all the 2DW232 with diamond mark is the low noise one. we have tested samples from several source and we found the date code start with 12-xx and 13-xx are most likely the low noise one. the newer one is probably not, such as the 14-xx to 15-xx we tested are kind of bad.

Pipelie, what is your noise test method?
 

Offline Pipelie

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #637 on: Yesterday at 06:58:58 am »
Hi edavid,

the LNA I'm using is this one. https://www.eevblog.com/forum/metrology/diy-low-frenquency-noise-meter/50/
also check post #195 for user manual. https://www.eevblog.com/forum/metrology/diy-low-frenquency-noise-meter/175/

test method:
[attachimg=1]

result of 2DW234:
[attachimg=2]

and others


 
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