Author Topic: AD587LQ  (Read 14238 times)

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Offline eurofoxTopic starter

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AD587LQ
« on: April 19, 2018, 02:38:46 pm »
Normally not available anymore  :horse:

This ic was used in the venerable Geller lab SVR-T in ceramic version.

But I order 5 IC's from Aliexpress, I don't no if they are new, used, fake but I'll take the risk since it is cheap  :-DD

eurofox
« Last Edit: May 23, 2018, 03:06:45 pm by eurofox »
eurofox
 

Offline cellularmitosis

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Re: AD587LQ from Aliexpress
« Reply #1 on: April 19, 2018, 03:31:06 pm »
I took a similar risk on a few LQ's from taobao.  I plugged them into my old Geller Labs reference board and they seemed to be wandering around.  I intend to take a closer look at them soon but it appears they could be fake or have been damaged.

However, the AD586LQ's I ordered don't seem to be wandering, so maybe it wasn't totally a bust?

Good luck!
LTZs: KX FX MX CX PX Frank A9 QX
 

Offline Andreas

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Re: AD587LQ from Aliexpress
« Reply #2 on: April 19, 2018, 06:52:48 pm »
but I'll take the risk since it is cheap

I hope it is worth the effort that you need to distinguish them from  being genuine.
Some tips for quick checks:
- test the 1/f noise (perhaps they have sold a bandgap reference which has a factor 3-5 more noise).
- test the pin voltages (especially pin 8 the internal divided reference voltage and pin 3 which is usually the temperature output pin on cheaper band gaps).

I personally do not believe that you can get genuine unobtanium devices.

with best regards

Andreas
« Last Edit: April 19, 2018, 06:55:07 pm by Andreas »
 

Offline eurofoxTopic starter

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Re: AD587LQ from Aliexpress
« Reply #3 on: May 23, 2018, 02:34:08 pm »
Got from Aliexpress the message  :blah: :blah: :blah: :blah:
I think the guy who try to sell this did not finally manage to get some of those litlle bad boy's  :-DD

But I found a company that can supply them, after 4 weeks delay .......

I will check them, they look genuine and it they are good I will post the place  :-DMM

eurofox
 

Offline Kosmic

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Re: AD587LQ
« Reply #4 on: May 23, 2018, 03:45:07 pm »
I'm looking at the specs and I don't see a lot of difference between AD587L and AD587U.

If the L version is not available anymore why not simply use the U version ?
 

Offline eurofoxTopic starter

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Re: AD587LQ
« Reply #5 on: May 23, 2018, 03:52:48 pm »
I'm looking at the specs and I don't see a lot of difference between AD587L and AD587U.

If the L version is not available anymore why not simply use the U version ?

You should read this https://www.eevblog.com/forum/testgear/geller-labs-svr-and-svr-t/50/

 :popcorn:
eurofox
 

Offline Kosmic

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Re: AD587LQ
« Reply #6 on: May 23, 2018, 04:11:00 pm »
I'm looking at the specs and I don't see a lot of difference between AD587L and AD587U.

If the L version is not available anymore why not simply use the U version ?

You should read this https://www.eevblog.com/forum/testgear/geller-labs-svr-and-svr-t/50/

 :popcorn:

Ho ok, I understand now  :)
 

Offline GigaJoe

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Re: AD587LQ
« Reply #7 on: May 23, 2018, 08:51:17 pm »
seen some for $20 ... kinda expensive.

is my understanding correct,  a letter just a thermal instability, or something more? (excluding items with wide range of temperature where manufacturing process may differ)   means it just more effort for thermo compensating circuit?
 

Offline Andreas

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Re: AD587LQ
« Reply #8 on: May 23, 2018, 09:40:24 pm »
Hello,

its either better selection for T.C. or better trimming.
But it is always a "average T.C." for the whole specified temperature range.
(measured at 3 temperatures: min, 25 deg C, and max of specified range e.g. 0..70 deg C or -55..125 deg C)

So if you use the device near room temperature the letter (grade) may be not helpful in all cases.

with best regards

Andreas

 

Offline GigaJoe

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Re: AD587LQ
« Reply #9 on: July 17, 2018, 03:18:23 am »
https://www.aliexpress.com/item/-/32881073708.html
got 6 reclaimed, mfg year  94, 95,91,04.  all good, "philippines" on the back ...
drifting, stability etc - unknown ...

UPD:  Seller started to ship relabeling chips ....
« Last Edit: December 03, 2018, 03:51:12 am by GigaJoe »
 

Offline MiDi

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Re: AD587LQ from Aliexpress
« Reply #10 on: September 26, 2018, 08:23:06 pm »
Got from Aliexpress the message  :blah: :blah: :blah: :blah:
I think the guy who try to sell this did not finally manage to get some of those litlle bad boy's  :-DD

But I found a company that can supply them, after 4 weeks delay .......

I will check them, they look genuine and it they are good I will post the place  :-DMM

Any results so far?
 

Offline Andreas

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Re: AD587LQ
« Reply #11 on: September 26, 2018, 09:58:35 pm »
Hello,

Any results so far?

My preliminary results:

I have ordered 2 times (8 pcs each) from GigaJoe s seller.
https://www.eevblog.com/forum/metrology/ad587lq-from-aliexpress/msg1677863/#msg1677863

He needed both times 1-2 weeks until I could see in the tracking system that he had sent them out.
When I asked him for delivery he answered something like he wanted to find the best source for me.
So obviously the seller does not have them on stock: so quality may vary.

Each reference has a different date code.
Devices are desoldered with partly bent pins.
Output voltage on all 16 devices is within +/-3 mV from 10V. So even with ageing within 5mV datasheet spec.
Pin 3 shows 0 V (so no temperature output signal like on some band-gaps)
Pin 8 and pin 5 are around 7V so obviously it is a buried zener reference.
1/f noise is around 4uVpp.

up to now 2 devices have frequently (every few seconds) popcorn noise. (but have not evaluated all data up to now).
It seems that the popcorn candidates had been marked with a black dot.
On the first batch I thought that it was some flux residue from desoldering so I had removed it.
On the 2nd batch I can correlate the marked device with the popcorn noise.

T.C. is still under evaluation.
Measured 12 devices up to now with < 2.5 ppm/K over +/-15 deg C span around room temperature.
2 devices showed up to 2-4 ppm (ageing) drift during T.C. measurement.

with best regards

Andreas
« Last Edit: September 27, 2018, 06:10:52 am by Andreas »
 
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Offline GigaJoe

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Re: AD587LQ
« Reply #12 on: September 26, 2018, 11:24:09 pm »
so, not bad in overall ...

my batch was send immediately ... ; no any labels
haven't able to test it,

one chip has strange output on pin 8 , like 1.$&% and up to 5V if heat it up ... aside of that pretty normal ...
and 1 completely fried. I can not tell it from this batch or another

JQ no LQ as described:
https://www.aliexpress.com/item/-/32832885977.html

plastic mostly fake .. don't even look at ... they actually do 10V output but nothing on pin-8 (even TC reasonable)
« Last Edit: September 26, 2018, 11:42:40 pm by GigaJoe »
 

Offline MiDi

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Re: AD587LQ
« Reply #13 on: September 27, 2018, 06:13:20 am »
Andreas, you now have new nickname (at least for me): the machine
 

Offline MiDi

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Re: AD587LQ
« Reply #14 on: October 21, 2018, 01:10:03 pm »
10 pcs arrived yesterday from GigaJoe:

« Last Edit: October 21, 2018, 01:15:06 pm by MiDi »
 

Offline branadic

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Re: AD587LQ
« Reply #15 on: October 21, 2018, 02:13:32 pm »
Looks like reference from 9540 has a crack?

-branadic-
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Offline MiDi

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Re: AD587LQ
« Reply #16 on: October 21, 2018, 02:42:02 pm »
No, it is something like epoxy, hard and very sticky - could not scratch it away with fingernails.
 

Offline Andreas

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Re: AD587LQ
« Reply #17 on: October 21, 2018, 05:35:41 pm »
2 devices showed up to 2-4 ppm (ageing) drift during T.C. measurement.

Update.

I examined one of the drifters more in detail.
Result: still about 1-2 ppm drift during one temperature cycle (15 hours).
So I think the two "drifters" will not be usable for my 10V references.

with best regards

Andreas
 

Offline MiDi

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Re: AD587LQ
« Reply #18 on: October 23, 2018, 06:30:27 pm »
6 came DOA, 4 are very good within specs (worst is +2mV, best -0.5mV).
Seller refunded 6 pcs. immediatly.
 

Offline syau

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Re: AD587LQ
« Reply #19 on: October 24, 2018, 09:55:31 am »
Received my batch of shipment this Monday, 3 out of 10 DOA. The remaining 7 all within specification which the best one is only +2ppm  :)
 

Offline Macbeth

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Re: AD587LQ
« Reply #20 on: November 10, 2018, 02:58:03 pm »
Ordered 6 from GigaJoes seller on 21/10 and received today. One is a dud, of the rest worst is +1.9mV, best +0.4mV. All CERDIP random dates.
 

Offline WillTurner

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Re: AD587LQ
« Reply #21 on: November 23, 2018, 05:08:01 am »
Voltage measurements of six parts from vendor LING LI "Shop1476012 Store" tested 28Aug18.

Datecode    Vtrim        Vout        Notes
9144             7.22       10.01     
9331             7.04        14.16      Bad
9816            13.91       14.34      Bad
9825            6 to 6.5    10.01      Vtrim unstable. Bad
0016              1.5          14.46      Bad
0422              7.06        10.01   

Hence, at least four bad out of six parts. Note that I am not implying in any way that the remaining two parts are "good"  :).

I sent the above information to the vendor, and their response was "Sorry, if the test does not pass, you should consider buying, because these ICs have been discontinued for a long time, and the market is also out of stock."

Based on the above, I could not recommend buying these. The AD587JQ through a trusted supply chain, and selection for tempco seems a better bet.
« Last Edit: December 06, 2018, 05:49:49 am by WillTurner »
 

Offline Andreas

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Re: AD587LQ
« Reply #22 on: November 23, 2018, 08:36:56 pm »
Hello,

with 20 brand new parts from DigiKey AD587JQ I had only 3 parts
with less than 2 ppm/K and less than 5(6)uVpp popcorn noise.
(ok 5 other parts were not far away but the rest completely useless for my needs).
And even then you can have large drift (more than 2 ppm/year after 5 kHrs)
after pre-selection.

At least those parts seem to be only mis-used and recycled parts. (and no fakes).
I already had some parts labeled MAX6350 in CERDIP which were definitively no buried zeners.
So buying such parts from a non official source is always a bit of gambling.
And in every case you need the equipment for noise and drift tests.

With best regards

Andreas


 

Offline GigaJoe

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Re: AD587LQ
« Reply #23 on: November 24, 2018, 06:18:10 pm »
Does only AD587 has PIN-8 as an output from zener ?  and no others in CDIP8 has it ?  Reason why I'm asking, got relabeled AD587,  but I'm suspicious it really 587 just a letters are relabeled.

last year bought got JQ (as pictured), not LQ ;  seller are reluctant to talk ...
https://www.aliexpress.com/item/-/32832885977.html
 

Offline Andreas

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Re: AD587LQ
« Reply #24 on: November 24, 2018, 06:47:44 pm »
Hello,

Ref102 also has pin 8 as noise reduction input. (SO-8)
VRE310 also noise reduction on Pin 8.
Some other (5V) references on Pin 3.

What makes you shure that there are no re-packaged components.
From SO8 to CERDIP?

I always check Pin 3, Pin 5 and Pin 8 for suspicious voltages on unknown references.

with best regards

Andreas

 


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