Author Topic: Please help identify this SOT23 diode?  (Read 1297 times)

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Offline ocsetTopic starter

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Please help identify this SOT23 diode?
« on: November 21, 2018, 07:44:07 pm »
Hi,
We have an offline  LED  lighting product from  an old company. It had been  running on the mains for two years.
It has a high voltage linear regulator just downstream of a mains diode bridge (there is no smoothing capacitor after  the diode bridge) . The regulator output is 2.5V. It just supplies a microcontroller. Connected from output to input of this regulator, is a SOT23 diode. This diode obviously stands off the rectified mains haversines (339Vpk).

An ex member of staff assures us that this diode is a BAS16……but BAS16 is only rated to 100V.     The diode itself is still functional,  and is pinned out like a BAS16. But surely such a low voltage diode wouldn’t have been able to survive going across the mains?

The diode has markings on it…….”kJB” ( or it might actually be “kJ8”)…and then perpendicular to this, it is marked “CN”.
Does anyone know what actual diode this might be?

BAS16 datasheet
https://www.vishay.com/docs/85539/bas16.pdf
« Last Edit: November 22, 2018, 07:12:09 pm by treez »
 

Offline mvs

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Re: Please help identify this SOT23 diode?
« Reply #1 on: November 21, 2018, 11:48:51 pm »
The diode has markings on it…….”CJB” ( or it might actually be “CJ8”)…and then perpendicular to this, it is marked “CN”.
Does anyone know what actual diode this might be?
CJ mark is used for mmbz4683, 3V zener diode.
"CN" is probably logo of ON semiconductor.
 
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Offline floobydust

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Re: Please help identify this SOT23 diode?
« Reply #2 on: November 22, 2018, 01:25:53 am »
Consider instead NXP TL431BQDBZR, SMD marking code "CJ%"
 
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Offline ocsetTopic starter

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Re: Please help identify this SOT23 diode?
« Reply #3 on: November 22, 2018, 07:12:44 pm »
Sorry, Ive a massive apology to make....it is marked "KJ8" (or "KJB") and not "CJ8"

...I was in the dept till late last night and had to leave before id got a good look.

Im pretty sure no SOT23  diode in the world is rated for mains voltage?

Aaah...solved it, its a 400v rated MMBD5004S, and it was made in Nov 2015
« Last Edit: November 22, 2018, 08:04:26 pm by treez »
 

Offline nali

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Re: Please help identify this SOT23 diode?
« Reply #4 on: November 22, 2018, 07:45:11 pm »
Try Googling "KJB" and "SOT23"? The very first hit gives MMBD5004, which is a 400V reverse breakdown part, the second hit gives the datasheet.

HTH
 


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