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SMD Component Identification Assistance

Garywoo

Apr 22, 2012
10
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Apr 22, 2012
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Hi everyone,

I've never had to decipher an SMD code before, so I thought I'd run my thoughts past you bunch of helpful folks to make sure I'm on the right track.

I've identified a failed SMD transistor (shorted) on an LED light strip controller PCB. The transistor outputs directly to the LED strip. There are 5 on the board, one for each colour channel (one removed in photo for testing).
The board runs on 24v from a CV 0.83A 20W power supply.

I'm pretty sure the component is a SOT-23 package. Length and width seem about right.
The markings on the component are WKC 72. I'm not quite sure which part of the marking is significant. I used this codebook as a reference. Initially I thought the WKC was the important part. This lead me to BCR119
nO3nTSy.png


However I'm not sure if this is right. If the 72 is the important part, then it could be 2N7002
mIN7KER.png


The silkscreen designates the component with an M. MOSFET? I'm thinking the 2N7002 is most likely correct. Am I correct in my assumption?
Looking at octopart, they come in a variety of continuous drain currents, from 115mA to 1.4A. What would be a safe choice for my application?

N5o7CCp.jpg


Thanks for any help or advice :D
 

dave9

Mar 5, 2017
1,188
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Mar 5, 2017
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1,188
Any n-channel SOT23 mosfet rated a fair amount over the single LED strand drive current, which I don't know (but you could measure, but don't really need to) so above the PSU 0.83A. They come in much higher currents than 1.4A but that should work.
 

davenn

Moderator
Sep 5, 2009
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I'm pretty sure the component is a SOT-23 package. Length and width seem about right.
The markings on the component are WKC 72. I'm not quite sure which part of the marking is significant. I used this codebook as a reference. Initially I thought the WKC was the important part. This lead me to BCR119


your logic doesn't follow
the chip as you stated has WKC but you found/hilited WKs which is likely to be a totally different device
you need to look for WKC

The 72 will be a manufacturing date/other info not directly related to the part type
 

Garywoo

Apr 22, 2012
10
Joined
Apr 22, 2012
Messages
10
Thanks for the tips guys.

The drive current for a single white LED strand is around 315mA.

After some further research, It would seem that WKC is a PMV20ENR:
wXZIErd.png

This looks particularly suitable, so I think I'll source a quantity and try them out.
 
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