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Help for SMD marking decoding

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yf1400

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Hi
I have a board with SMD parts from a special device. I have found the datasheet for all of them except 3 parts. These are 3 pin tiny smd parts. At the top overlay of the board beside all of these parts is written "Q_" (for example Q6). I think these are BJT or maybe MOSFETs. But I couldn't find these part numbers in the internet and even in some SMD marking books. I'm wondering if anyone can help me and find the datasheet for these parts. I think the they are manufactured in USA.
The marking on these parts are attached.
Best Regards

Q1.png
 

KlausST

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Hi,

Often the printed code is a combination of several informations.
* some digits represent the part
* some digits represent the manufacturer
* some digits represent the lot number or date code

That means that you may find not the complete code in the smd code books. Look for the first digits and if you think you have found a part then do some voltage measurement to test if the values fit to the datasheet.

The underlined _Z_ may be the the sign for Zetex.

Hope this helps
Klaus
 

FvM

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If you assume that only two characters are coding the part, you'll find suitable entries for all three. Personally, I would identify the device type with an ohmmeter and by tracing the circuit connections. If the possible range of devices fits the code, there's a good chance for a hit.
 

yf1400

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Hi dear KlausST
Thanks for your response.
For example I searched for 2A or 3F in SMD marking books and Internet. I found some parts for them. They are PNP Silicon Transistor or Zener Diode but based on my measurements this part is a MOSFET.
Where and How should I search for it?
I want to know if there is any complete reference for SMD parts.
thanks
 

KlausST

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I want to know if there is any complete reference for SMD parts.
thanks
I´m sorry, i dont think so.

Diode, Zener: because of the "Q" in the name for me it sounds morelike a fet or bjt

Klaus
 

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