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I have been trying to identify these 2 transistors online with very little luck. Not sure if they are obsolete but the PCB was bought in 2016.

F5EZ2

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  • \$\begingroup\$ Thanks for posting reasonable pictures. Please tell us about the board that they are on. What kind of product is it, and what do you THINK the transistors might be for? Are you sure they are transistors, since diodes can also come in SOT23. A zoomed out picture might be a good addition to the question. \$\endgroup\$
    – user57037
    Apr 8, 2018 at 6:58
  • \$\begingroup\$ I just added a 3rd picture so you can see it looks a PNP and an NPN because of the Ground? All pins are routed and I have a 2N7002P sitting on the board for size reference \$\endgroup\$
    – Andrew8078
    Apr 8, 2018 at 7:51
  • \$\begingroup\$ As @mkeith said, these could be diodes, analogue switches, voltage references, BJTs, MOSFETs...the list is very extensive sadly. The designator is obviously a good clue, and I can see a "Q1" which is almost certainly a transistor. So as he said, a zoomed out photo would be great! \$\endgroup\$
    – DSWG
    Apr 8, 2018 at 23:31
  • \$\begingroup\$ Maybe Q1 is a high side PMOS switch. R4 is the resistor from source to gate. The other transistor pulls down the gate of Q1 to turn it on. Traces are small. Probably not a lot of current. So replace Q1 with BSS84 and the other with BSS138. Of course, there are a lot of guesses there. But I think Q1 is probably PMOS. I don't think it is a BJT because there is nothing in series with the gate (which would be the base if it was PNP). The other COULD be BJT. Maybe follow gate/base net to search for clues. \$\endgroup\$
    – user57037
    Apr 8, 2018 at 23:55
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    \$\begingroup\$ '1A' may be BC846A/MMBT3904, a very popular general purpose NPN transistor. \$\endgroup\$ Apr 9, 2018 at 1:28

1 Answer 1

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The style of marking on the first one (F5EZ2) looks to me like some member of the IRLML "family" of MOSFETS. It could be IRLML6401 (letter "F"). Here's datasheet and marking info: https://mouser.com/datasheet/2/196/irlml6401pbf-1228277.pdf

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  • \$\begingroup\$ That link is bad. Can you fix it? \$\endgroup\$
    – user57037
    Apr 11, 2018 at 4:59
  • \$\begingroup\$ Link fixed. I hope this one works. If not, just google "IRLML6401". \$\endgroup\$
    – desqa
    Apr 11, 2018 at 5:10
  • \$\begingroup\$ I think this is the answer. \$\endgroup\$
    – user57037
    Apr 11, 2018 at 5:49

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