I have a BLDC driver board and am having trouble identifying a component. Its PCB label is X3 so I initially assumed it was a fuse of some type. However it is connected in 3 spots. I searched smd code tables etc but can't find it. Looks like 470C is printed on the component but could be 47OC etc. Also picture of inside of same component after the guy in the store wanted to prove to me that it was a removable fuse - which it wasn't. Any help is appreciated.

Thank you for the responses so far. I've drawn a crude circuit diagram which I should have included to start with. Could they be Mosfets? eg BSS138 Found some I2C bi-directional level shifter circuits which had some similarities. Also Ive tried to get some better closeups of the "pulled apart" component. drawing component intact and pulled apart

I am limited to 2 links so combined images into one.

  • 3
    \$\begingroup\$ "X" is often used for Xtal or Crystal. I don't think this is actually a crystal but it could be a (470kHz?) ceramic resonator, they often have 3 pins. \$\endgroup\$
    – user16324
    Jul 29, 2017 at 1:19
  • \$\begingroup\$ From the internal construction, maybe it was a pi filter or ESD filter. Can you figure out the circuit? \$\endgroup\$ Jul 29, 2017 at 2:01
  • \$\begingroup\$ True X is reserved for Xtal but in this case in between 27R0 and 226 (22uF) parts, but judging its foil construction, it could be a shielded choke, The only issue is what caused the fault? \$\endgroup\$ Jul 29, 2017 at 2:28
  • \$\begingroup\$ This is a motor control board. This is a special area of engineering-craftsmanship. The part could be anything, transistor, sensor, who knows. A sketch of overall connectivity would help. \$\endgroup\$ Jul 29, 2017 at 2:51
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    \$\begingroup\$ Draw a circuit that is "around" this part. It could help a lot. \$\endgroup\$ Jul 29, 2017 at 4:51

1 Answer 1


Looks like it's an LC filter. Possibly this one:


Marking code of 470C makes sense for this part, looks like it could be an ELKE470FA with a 100 MHz cutoff frequency, a 47 pF cap, and a "C" month code.

  • \$\begingroup\$ I think you are right. Cosmetically inside and out it appears identical. Thanks \$\endgroup\$
    – bobox
    Jul 30, 2017 at 4:46

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