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SMD component codes

Discussion in 'Electronic Design' started by John Popelish, May 3, 2005.

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  1. Does anyone have a link to a list of SMD component codes? I am trying
    to identify what I think is a dual RF transistor in what looks like a
    SOT-23-6 package with an S169 code etched into it.

    I can find lots of codes, not in catalogs, but only by calling up
    individual data sheets.
  2. John Popelish said

  3. Boris Mohar

    Boris Mohar Guest

  4. Pooh Bear

    Pooh Bear Guest

    There's precious little space to put a component code on SOT23.

    I always refer to the data sheet. It's often just one letter and one
    numeral. Not much help if you don't have the schematic.

  5. Another good one for the files.

    But on further examination, I am beginning to think the device is
    something more complicated and proprietary than a couple of
    transistors. I think it is a dual antenna switch (transmit and
    receive). It is connected between the antennas on a 2.4 G Hz WAN
    board. I probably can't get them even if I can identify them. Sigh.
  6. Joerg

    Joerg Guest

    Hello John,
    Could it be an arrangement of PIN diodes?

    Regards, Joerg
  7. Greg Neff

    Greg Neff Guest

    Nope, no link. Two things to consider:

    1) Are you sure it's S169 and not 691S?

    2) The last character (or two) may be a date code.

    Our inventory control system includes the part marking of each
    approved component (where applicable), so that the parts that we use
    can be identified and the markings can be searched. Unfortunately,
    this doesn't help you.

    SMD part markings is a major pet peeve of mine. There are many cases
    where the markings are not specified, even in the data sheet. This is
    especially true for logic families. When I put a new part in our
    database I often have to wait to get a sample to see how the part is
    marked so that I can enter that data. To make matters worse I have
    seen cases where the markings don't match the format specified in the
    data sheet, which means that we have to chase after the manufacturer
    for clarification.

    While I'm ranting, it drives me nuts that some manufacturers are using
    the same part numbers for both lead and lead-free finishes. They
    publish dates at which the finish will change, but now we have to use
    date codes to identify which parts are which. We are still trying to
    figure out how to modify our inventory control system to deal with
    this, to ensure that parts don't get mixed up. Like, what happens if
    we need lead-free, and a disti sends us parts with an older date code?
    Will the disti let us return them? And what then? What happens to
    our production schedule when these old parts arrive and we suddenly
    realize that we have to buy newer parts elsewhere? Didn't anyone

    And then there are things like Vishay formerly BC Components formerly
    Philips resistors. At least two different part numbers for the same
    thing, plus a NAFTA part number that does not appear in any data
    sheet, together multiplied by the number of packaging and lead length
    options. What a nightmare.


    Greg Neff
    VP Engineering
    *Microsym* Computers Inc.
  8. Robert Kent

    Robert Kent Guest

    Close. I expect it is a Skyworks AS169-73 SPDT switch, most likely used
    to select between antennas based on signal strength.

    Here's a schematic for a Prism2 WLAN card reference implementation
    which uses two of these chips, one for antenna discrimination and one
    for TX/RX switching:

    Credit where credit is due, here's the page where I found the above

    Here is a datasheet for the part:

    And what have we here, but a company offering samples and small sale
    quantities of Skyworks's current RF switch product line
    (disclaimer--never dealt with these guys):

    The AS169-73 is not listed but you might be able to substitute a part
    with similar specs, such as the AS193-73.
  9. I think you may be right, The layout is right and the component
    values I can read match this schematic.
    Thank you very much. This is the info I was looking for.
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