Author Topic: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x  (Read 234910 times)

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Online Andreas

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #175 on: November 18, 2016, 05:52:48 am »

Thank you for preparing this translation, but I think the listed pinout is incorrect.  For the devices I received from VintageNut, pins 1 and 2 are anodes, and pin 3 is the common cathode.

Hello,

The translation corresponds to the picture from the datasheet. (first page on the thread).
Do you really measure 5.6 instead of 0.7V on the ground referenced diode when using a pull-up resistor?

With best regards

Andreas
 

Offline edavid

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #176 on: November 18, 2016, 05:57:26 am »
Thank you for preparing this translation, but I think the listed pinout is incorrect.  For the devices I received from VintageNut, pins 1 and 2 are anodes, and pin 3 is the common cathode.
The translation corresponds to the picture from the datasheet. (first page on the thread).
Yes, that is also incorrect (or doesn't match the parts I received).  Very odd.

Quote
Do you really measure 5.6 instead of 0.7V on the ground referenced diode when using a pull-up resistor?
Sorry, I don't understand this question.
 

Online Andreas

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #177 on: November 18, 2016, 06:27:25 am »
if you take the cirquit from Alex:

https://www.eevblog.com/forum/metrology/ultra-low-noise-reference-2dw232-2dw233-2dw23x/msg1068444/#msg1068444
e.g. with 15V supply and resistor = 1K

what voltage do you measure between Pin 3 (case of zener) and ground?

With best regards

Andreas
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #178 on: November 18, 2016, 08:51:06 am »
I've measured (by a multimeter diode test only so far) one of the devices I've received and it is indeed a common cathode configuration, as shown on the attached diagram.

Cheers

Alex
 

Online Andreas

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #179 on: November 18, 2016, 10:35:23 am »
So its more difficult to measure the chip temperature since the forward diode is not referred to GND.

With best regards

Andreas
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #180 on: November 18, 2016, 10:52:06 am »
So its more difficult to measure the chip temperature since the forward diode is not referred to GND.

With best regards

Andreas

It will be easy in a negative reference configuration though ;) . In a positive reference the diode can still be used easily for a temperature stabilization with an external heater.

Cheers

Alex
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #181 on: November 18, 2016, 01:45:05 pm »
I'm running a measurement on the first sample right now. The circuit is attached. R1 is actually a resistor decade set at 515 Ohm, that is a reasonably stable point. The zener is connected through an IC socket, the 10V source is my JVR reference, so it is quite stable, C1 is a Mylar film capacitor. Right now I'm using the 34465A. I might leave it running over the weekend with 3558A though.

Cheers

Alex

P.S. - first impressions are ... interesting. Very little random noise but the device is (relatively) sensitive to temperature variations and air movements. I suspect that it can only be useful with a good temperature stabilizing loop. With ~7.5mA and 6 Volts the dissipation is quite high and so is self-heating. As a result, any air movements produce noticeable voltage shifts (few ppm even with a good foam envelope around the device). The dynamic resistance at 7.5mA is about 13-14 Ohm. We'll see how it performs over the weekend.
« Last Edit: November 18, 2016, 03:16:05 pm by Alex Nikitin »
 

Offline edavid

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #182 on: November 18, 2016, 04:20:50 pm »
P.S. - first impressions are ... interesting. Very little random noise but the device is (relatively) sensitive to temperature variations and air movements. I suspect that it can only be useful with a good temperature stabilizing loop. With ~7.5mA and 6 Volts the dissipation is quite high and so is self-heating. As a result, any air movements produce noticeable voltage shifts (few ppm even with a good foam envelope around the device). The dynamic resistance at 7.5mA is about 13-14 Ohm. We'll see how it performs over the weekend.

Is your device a 2DW232 or 2DW233?  I know zlymex told us not to pay much attention to the nominal current, but...
 

Offline zlymexTopic starter

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #183 on: November 18, 2016, 05:02:15 pm »
..... With ~7.5mA and 6 Volts the dissipation is quite high and so is self-heating. As a result, any air movements produce noticeable voltage shifts (few ppm even with a good foam envelope around the device). ......
The foam should be in touch with the case and legs, leaving as small gaps as possible. I just use tissues.
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #184 on: November 18, 2016, 05:56:33 pm »
P.S. - first impressions are ... interesting. Very little random noise but the device is (relatively) sensitive to temperature variations and air movements. I suspect that it can only be useful with a good temperature stabilizing loop. With ~7.5mA and 6 Volts the dissipation is quite high and so is self-heating. As a result, any air movements produce noticeable voltage shifts (few ppm even with a good foam envelope around the device). The dynamic resistance at 7.5mA is about 13-14 Ohm. We'll see how it performs over the weekend.

Is your device a 2DW232 or 2DW233?  I know zlymex told us not to pay much attention to the nominal current, but...

2DW232

Cheers

Alex
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #185 on: November 18, 2016, 07:43:29 pm »
Here is a one hour run result from this afternoon, the temperature probe is inside the foam enclosure but not touching the zener.

Cheers

Alex



« Last Edit: November 18, 2016, 07:45:53 pm by Alex Nikitin »
 
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Offline Kleinstein

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #186 on: November 18, 2016, 07:59:38 pm »
This does not look good at all. I might need a better adjustment of the current to get a low TC and thus less sensitivity to temperature variations. Keep in mind that the optimum current depends on the temperature - so it could be a different value with the added foam.

To check if the variations are temperature related one cold also monitor the forward diode only. This might also help to find the right current.
 

Offline Gyro

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #187 on: November 18, 2016, 10:13:10 pm »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?
Best Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Alex Nikitin

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #188 on: November 18, 2016, 10:16:30 pm »
This does not look good at all.

I disagree. The temperature fluctuations are on the order of 50ppm/C or less. I didn't have time to find a better current as every time the current is changed the zener changes the temperature and it takes a while to get to the optimum point. But that is possible to resolve in various ways. Most important for me is how smooth the curve is. The LTZ1000 under similar conditions looks mush more "rugged" (though completely flat  ;) ).

Cheers

Alex
 

Offline edavid

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #189 on: November 18, 2016, 10:39:39 pm »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?

All of mine have the dot on pin 1 (near the tab).

 

Offline technix

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #190 on: November 19, 2016, 05:41:26 am »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?

All of mine have the dot on pin 1 (near the tab).
That dot is used to tell parts apart when you ordered it in unmarked form. 2DW233 got a yellow dot, 2DW234 red, 2DW236 grey.
 
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Offline Gyro

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #191 on: November 19, 2016, 11:07:12 am »
Thanks technix, that makes more sense, I haven't seen the package part number lettering yet (maybe today with luck)  It also clears a small nagging worry that the dot might mean 'reject' (in the same way that die testers do on a wafer) :D. It looks as if the target zero Tc current for these parts will be closer to 10mA (2DW234) rather than 7.5mA then, that should save some time.
« Last Edit: November 19, 2016, 11:10:40 am by Gyro »
Best Regards, Chris

"Victor Meldrew, the Crimson Avenger!"
 

Offline Seekonk

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #192 on: November 19, 2016, 04:04:58 pm »

[/quote]
That dot is used to tell parts apart when you ordered it in unmarked form. 2DW233 got a yellow dot, 2DW234 red, 2DW236 grey.
[/quote]

So, they are all marked 2DW232 and the red dot makes them a 2DW234.

Now the work begins.

Many thanks to zlymex  and VintageNut.

 

Offline edavid

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #193 on: November 19, 2016, 04:13:44 pm »

Quote
That dot is used to tell parts apart when you ordered it in unmarked form. 2DW233 got a yellow dot, 2DW234 red, 2DW236 grey.

So, they are all marked 2DW232 and the red dot makes them a 2DW234.

Wait, he didn't say that!

zlymex or technix, what does it mean when the part is marked 2DW232 *and* it has a red dot?
 

Offline technix

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #194 on: November 19, 2016, 05:29:51 pm »

Quote
That dot is used to tell parts apart when you ordered it in unmarked form. 2DW233 got a yellow dot, 2DW234 red, 2DW236 grey.

So, they are all marked 2DW232 and the red dot makes them a 2DW234.

Wait, he didn't say that!

zlymex or technix, what does it mean when the part is marked 2DW232 *and* it has a red dot?

I will confirm it with the factory next Monday. Stop using it for now though, they may be technically counterfeits.
 

Offline zlymexTopic starter

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #195 on: November 20, 2016, 05:23:19 am »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?
Dotted pin is negative terminal, un-dotted pin(of 1 or 2) is positive terminal, pin 3 for reserve. This is from a datasheet.

Red dot is for 2DW232, yellow dot is for 2DW233, pink dot is for 2DW234, green dot is for 2DW235.
 
 

Offline technix

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #196 on: November 20, 2016, 06:43:12 am »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?
Dotted pin is negative terminal, un-dotted pin(of 1 or 2) is positive terminal, pin 3 for reserve. This is from a datasheet.

Red dot is for 2DW232, yellow dot is for 2DW233, pink dot is for 2DW234, green dot is for 2DW235.
Maybe we are referring to a different datasheet? I have obtained a full catalog from the factory and it have said none of that.
 

Offline zlymexTopic starter

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #197 on: November 20, 2016, 06:49:45 am »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?
Dotted pin is negative terminal, un-dotted pin(of 1 or 2) is positive terminal, pin 3 for reserve. This is from a datasheet.

Red dot is for 2DW232, yellow dot is for 2DW233, pink dot is for 2DW234, green dot is for 2DW235.
Maybe we are referring to a different datasheet? I have obtained a full catalog from the factory and it have said none of that.

 

Offline technix

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #198 on: November 20, 2016, 10:35:08 am »
Just a thought, is the Red dot on the package (if the same as zlymex's photo) added on test to indicate which diode has the most stable zener breakdown characteristics?
Dotted pin is negative terminal, un-dotted pin(of 1 or 2) is positive terminal, pin 3 for reserve. This is from a datasheet.

Red dot is for 2DW232, yellow dot is for 2DW233, pink dot is for 2DW234, green dot is for 2DW235.
Maybe we are referring to a different datasheet? I have obtained a full catalog from the factory and it have said none of that.

This is definitely a different datasheet I am referring to. I have posted a translated datasheet based on what I got.
 

Offline BravoV

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Re: Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x
« Reply #199 on: November 20, 2016, 12:35:57 pm »
So there are "multiple" different datasheets spreading in the wild ?  :palm:


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