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What is this SMD component?

Discussion in 'Datasheets, Manuals and Component Identification' started by alert, Dec 14, 2017.

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  1. alert


    Dec 14, 2017
    what is this smd component

    Attached Files:

    • D.png
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  2. Alec_t


    Jul 7, 2015
    Welcome to EP!
    If the marking on it is a zero, then it is a shorting link.
    davenn likes this.
  3. kellys_eye


    Jun 25, 2010
    It's a little green rectangular thing...... ( @Alec_t the marking is a 'D' )

    Have you measured it? Diode perhaps? Maybe an inductor.
  4. Wiginometry


    Nov 29, 2017
    Umm... a tiny smd that requires a microscope to install?
    Though this card looks familiar what was it?
    I think I have one of these somewhere...
    I have to agree with @kellys_eye definitely measure it that'll give you a better idea of what it's doing,
    Though I'm not sure what the marking is for best guess is it's some weird off the wall tantalum capacitor.
  5. alert


    Dec 14, 2017
    i think the component with marking D on it is an inductor and component with marking 8401 is a power amplifier but i cannot find a data sheet can some please tell me what it is
    Thanks D.png
  6. kellys_eye


    Jun 25, 2010
    There does seem to be a 'bar' marking on the device indicating a polarity - hence the 'diode' assumption but a quick test with a multimeter should tell.
  7. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Sir alert . . . .

    Careful there now . . .CAREFUL . . .as you are now answering your own question.

    The way that I am "reading the board" is that RED OVAL circled SM semi is not following the most common lead assignment protocol, so lets basically see that the center pin is going to the ground plane of the PCB, whereas that would most commonly be the output of a discrete semiconductor. Soooooo . . . lets make it a POWER RF amplifier with the far right lead being its input and the far left lead, being its RF output.
    My best read on its cryptic numbering assignment is also with it being an "8401".

    Why for . . . . .you additionally . . .did NOT tell us what this WHOLE DEE-VICE IS ? , as well as its brand and model number.
    I could only visually relate to it as being a Pulse code modulated ? 433 MHZ ? transmitter.
    Now, in my referencing to the on board components, I am seeing the right bottom corners Piezo alert transducer, an then the possible CAT 5 input and USB inputs along the side.
    Top right corner is the POWER input and its related power handling being just to the left, with at least 1 regulator being involved . . as being the IC1 . The dry tantalum 100 ufd unit tells us that this equipment operates with a max input voltage of less that 25 VDC.
    Now in referencing back to the Piezo again, we see the 20 pin ICSP . . .IC3 . . . as BPS101 ? or BP5101 OR possibly its line above it, as ??32 . . .you tell us .
    If we knew that, the possibly is that there could be an application note with all of the auxiliary support circuitry being shown as a schematic.
    And there, to IC3's side, is its its support xtal X1.
    Then you take its low level RF output at the right YELLOW line that passes up to a lattice filtering network of RC and L discretes with the white units being the inductance, it then routes to the left to input to the right terminal of the 8401 power amp IC.
    Then go back to the power supply and catch the main HEAVIER RED BUSS routing to the left and catching a few ceramic RF bypassing and finally your . . . . ta daaaaa . . . L6 . . . . inductive load for that amplifier.
    RF output passes to the left thru the PURPLE line route into L9 and L10 and finally comes to a 6 pin IC . . .IC6 . . . which I would suspect to be an RF rated FET switch(es) that receives its activation via the single YELLOW line that goes over to the OTHER yellow line at the top of that IC3 . ( With a possibility . . . . .of the two heavier side busses at the left side of IC3 also relating to power or additional signal info coming into IC6. .
    Your FET(s) modulate your PURPLE RF line and then it feeds thru the ceramic C31 coupling capacitor and then on down to your RF output connector.

    NOW . . to test . . . . do you know how to take a 5 pf silver mica (or ceramic) sampling / DC isolation capacitor and feed it into a 1N34 /1N60 or Schottky diode (1N5711) to thereby rectify your RF and then use a .01 by pass to ground at the far end of the diode and shunt across that .01 with a 10K load resistor.
    The the 10K will have a milli volt ranged DC voltage level being read across it, as a RF signal is being inputted at the 5 pico farad capacitor.
    If you sub in a scope across the 10K load resistor, you should see the digital modulation train being impressed upon the RF.

    MAGGED UP and marked REFERENCING . . . .


    73's de Edd
    Last edited: Dec 15, 2017
  8. Arouse1973

    Arouse1973 Adam

    Dec 18, 2013
  9. kellys_eye


    Jun 25, 2010
    I had a notion that the active device was a three terminal regulator - given the component distribution around it - and with the expanded view as the presence of the bias potentiometer this would seem to increase the likelihood.

    The 'bar' on the package does lead one to believe it has some polarity issue though, hence it may be a diode.
  10. davenn

    davenn Moderator

    Sep 5, 2009
    I have these on dozens of pieces of gear I service at work
    and they ALL are labelled on the silkscreen as R for resistor
  11. 73's de Edd

    73's de Edd

    Aug 21, 2015
    Oye . . .OYE . . . . .

    When the party of the first part . . .thrice removed . . . returns . . . . .lets just have him place a small neo-biddy-ninny-ninny -yum-yum magnet up against said "D" part, and just see how much of a resistor that it is. (Considering that there is being some slight magnetic influence to chip resistors, related to production line robo- handling. ) ( AND for me, in finding ones that I drop down into the carpet )
    BUT nothing like the attraction that will be given to that magnet by the hunk of ferrite /or/ powdered iron that will be within that chokes core.
    I still see it as being an RF choke element / and / that SMD PWR IC's output load , with its isolating the RF from grounding out thru the RED lines incoming DC supply..
    AND are the adjunct silk screen identifier assignments being ignored ?

    Last edited: Dec 16, 2017
  12. kellys_eye


    Jun 25, 2010
    I think the OP could put us all out of our misery and just measure the darned thing!
    Arouse1973 and davenn like this.
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