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Harris IC ID

Discussion in 'Electronic Repair' started by Samuel M. Goldwasser, Jan 30, 2009.

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  1. I have a PCB with a part marked:


    It's an 8 pin SOIC, with power (+5 VDC) at pin 8 and GND at pin 4.
    Could be an op-amp or TTL based on expected function.

    I'm assuming Harris - the "H" is a bit bolder than the rest.

    Only a few years old, not ancient.

    Google seems to have no clue except that the H721A has been asked about
    on a sci* group in the past, apparently without a solution.

    It really shouldn't be anything unusual or custom,

    Some of it's pins are connected to the outside world via 100 ohm series
    resistors. Part of an interlock on a laser.

    Any info appreciated.


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  2. Franc Zabkar

    Franc Zabkar Guest

    FWIW, I found this tiny snippet of info on a part that may be related
    to the H721A:



    Another clue may be this post:\1999\11\24\071335a.txt

    The author writes:

    "I'm trying to find the manufacturer of a IC in the PicStart board,
    it's a SO8 dual SPST switch and it's marked H721A.

    I've found the analog device ADG721, but I'd like to know others

    Microchip's PicStart manual states that the "PICSTART Plus development
    programmer features ... special circuit design techniques to enhance
    ESD protection."

    Here is the datasheet for the ADG721/722/723:

    It states that "the ADG721/ADG722/ADG723 features proprietary ESD
    protection circuitry". The part is described as a "CMOS Low Voltage 4V
    Dual SPST Switch".

    I suspect that the H721A is in fact compatible with the ADG721.

    - Franc Zabkar
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