Identifying components : Diode Zener

Discussion in 'General Electronics Chat' started by Dedi, Apr 1, 2015.

  1. Dedi

    Thread Starter New Member

    Jun 7, 2014
    8
    0
    Hello All,

    I had the same problem as the previous thread.
    Can u help me, what is type number of this diode zener with marking " MMM. "?
    see the image attachment

    thanks.
     
  2. Papabravo

    Expert

    Feb 24, 2006
    10,144
    1,790
    I get no hits on my cross reference. What makes you think it is a zener diode?
     
  3. Dedi

    Thread Starter New Member

    Jun 7, 2014
    8
    0
    it is part of a series of communication and connect with MCP2551 IC.
    (-)Zener to pin5 and 6 of the MCP2551.
     
  4. Dedi

    Thread Starter New Member

    Jun 7, 2014
    8
    0
    CORRECT: .......... (-)Zener to pin 6 and 7 of the MCP2551.
     
  5. Papabravo

    Expert

    Feb 24, 2006
    10,144
    1,790
    What are they doing with a zener in those positions of a CAN transceiver!!??

    Pin 6 is CANL, it should be connected to nothing but the bus.
    Pin 7 is CANH, it should be connected to nothing but the bus.

    A terminator if it exists should be on the cable and not on the PCB of ANY node.
    Especially bad is a terminator on the PCB with a JUMPER.

    The unit will work just fine without them.
     
  6. #12

    Expert

    Nov 30, 2010
    16,298
    6,808
    The only search results I got were, "24V bilateral MOV".
    I think that would fit in your position from CANH to CANL but I have no background in that area.
    Refer to Papabravo for better information than I can provide.
     
  7. Dedi

    Thread Starter New Member

    Jun 7, 2014
    8
    0
    thanks for your time.

    I just saw on the same circuit, may be just the previous model.. MCP2551 connected with a zener diode SOT-23 with marking "EL15" = ESDA14V2L, and it's for ESD Protection.

    I wonder,the zener diode breaks down all on the PCB.
    I read the datasheet "High ESD protection level : up to 25 kV"

    you have a recommendation for replacement parts?
     
    Last edited: Apr 2, 2015
  8. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
    2,809
    834
    Have you noticed that there is an "Edit" button on your threads? You can make corrections in the original post. Its usual to make a note at the end, stating why you made an edit.

    Does the PCB have a symbol printed on it? Can you provide a picture? Does it look like this:

    Varistor_symbol_1.png Then it is a varistor, not a zener diode.
     
  9. Dedi

    Thread Starter New Member

    Jun 7, 2014
    8
    0
    no,just"DZ.."
     
Loading...