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LM2678 Webench CAD tools

Other Parts Discussed in Thread: LM2678
Hello,
Webench CAD tools used to get the LM2678 (Adj.) library (Date: 14.08.2015). When testing the PCB was noticed that the Schematic Symbol does not match the PCB Symbol?
Thank you.
  • Hi Monica,

    You are correct that the schematic symbol pin mapping to the LM2678-ADJ package are not one-to-one for any of the three packages offered (TO-220, DDPAK or VSON-14). WEBENCH's symbol is simplified for a cleaner schematic presentation. However, the cad file should offered the correct pin mapping of all orderable part numbers with proper pin names and pin numbers. For example, both the PCB layout and schematic of the DDPAK part, the switch node should be pin #1 and named as "SWITCH" or "SWITCH OUTPUT" per datasheet. Please let us know if you are seeing something different.

     

  • Hi Howard,

    The Layout Symbol does not match the LM2678 (DDPAK) pinning. There were two different Libraries used, both downloaded via WEBENCH but at different dates, and both had problems.

    The pinning of the version downloaded in August was totally wrong, it starts with pin 5 ends with pin 6 and the other pins are also mixed (see picture below).  

    The problem with the Library downloaded in November is that the switching pin "SW" is displayed in the schematic as pin 8 and pin 8 in the Layout is the Heatsink Pad of the LM2678 (see picture below). 

    Regards
    Andi

  • Hi Andi,

    I apologize for the wrong pin mapping of the LM2678 DDPAK was posted.  I just checked the latest bxl online for the LM2678S part and It looks ok.

    Please re-download the latest or use the attached zipped file below.

    LM2678_KTW_7.zip

     I'm sorry for the inconvenience.