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PIC16f628 basics

Discussion in 'Electronic Design' started by Jack// ani, Oct 26, 2004.

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  1. Jack// ani

    Jack// ani Guest

    Hi there

    Will anybody out there please tell me what's the difference between an
    18pin and a 20pin PIC16f628?

    All I can figure out is, 20pin dip is having one extra Vdd and Vss
    pins. I don't understand the need of those duplicate pins!

    Thanks
     
  2. Leon Heller

    Leon Heller Guest

    It's probably because there isn't a standard 18 pin SSOP package, so
    Microchip had to use the 20 pin package. Rather than make the two additional
    pins NC, they connected them to Vdd and Vss.

    Leon
     
  3. xray

    xray Guest

    Dang! Email Microchip. They may give you a reward for pointing out that
    they are wasting pins.

    It may become a bit clearer if you check this link
    http://www.semiconwell.com/packages/tssop.htm
    and look at the specifications for the standard 18-pin TSSOP package.

    What? Can't find it?
     
  4. Jack// ani

    Jack// ani Guest

    sounds as if you are very familiar with that reward, did you once got
    it? Just joking be cool!!
    anyway thanks Leon and xray.
     
  5. Clarence

    Clarence Guest

    Check out

    http://ww1.microchip.com/downloads/en/DeviceDoc/40300c.pdf

    Page 2.

    There are 18 Pin soic package.

    However that does not answer the question.
     
  6. Yeah, there's an 18 pin DIP too. The question relates to the SSOP
    package.

    Not as bad as parts like the QFN version of the 18F1220 with 8 N/C
    pins. Though on those the 20 pin SSOP and 28 pin QFN packages are used
    to advantage over the DIP18 in bringing out two separate analog supply
    pins.


    Best regards,
    Spehro Pefhany
     
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