+ Post New Thread
Results 1 to 11 of 11
  1. #1
    Member level 1
    Points: 419, Level: 4

    Join Date
    Jul 2011
    Posts
    40
    Helped
    0 / 0
    Points
    419
    Level
    4

    Standard Decaps in Industry

    Hello,
    Just wondering if anyone is able to tell me what the typical decap structures used in industry look like? Are they generally MOScaps or some other structure? Are the same structures used for whitespace decaps as well as those used within standards cells?
    Thank you in advance :o)

  2. #2
    Advanced Member level 5
    Points: 37,620, Level: 47
    mister_rf's Avatar
    Join Date
    Feb 2008
    Location
    Romania
    Posts
    1,874
    Helped
    1049 / 1049
    Points
    37,620
    Level
    47

    Re: Standard Decaps in Industry

    Some info here:
    DEcap Cells



    •   AltAdvertisement

        
       

  3. #3
    Advanced Member level 4
    Points: 10,068, Level: 24
    leo_o2's Avatar
    Join Date
    Sep 2004
    Location
    China
    Posts
    1,324
    Helped
    278 / 278
    Points
    10,068
    Level
    24

    Re: Standard Decaps in Industry

    What's your meaning for Decap? Decoupling Capacitor?



    •   AltAdvertisement

        
       

  4. #4
    Advanced Member level 5
    Points: 37,620, Level: 47
    mister_rf's Avatar
    Join Date
    Feb 2008
    Location
    Romania
    Posts
    1,874
    Helped
    1049 / 1049
    Points
    37,620
    Level
    47

    Re: Standard Decaps in Industry

    Yes, on-chip decoupling capacitors = decaps.



    •   AltAdvertisement

        
       

  5. #5
    Member level 1
    Points: 419, Level: 4

    Join Date
    Jul 2011
    Posts
    40
    Helped
    0 / 0
    Points
    419
    Level
    4

    Re: Standard Decaps in Industry

    Thank you mister_rf for your kind response and for sending the link to the document. I'm familiar with the document and have read numerous papers on decaps, however, I was curious about what the general practice in industry was regarding decaps. Which structures are preferred, sizing, layout details, etc.?



  6. #6
    Advanced Member level 4
    Points: 10,068, Level: 24
    leo_o2's Avatar
    Join Date
    Sep 2004
    Location
    China
    Posts
    1,324
    Helped
    278 / 278
    Points
    10,068
    Level
    24

    Re: Standard Decaps in Industry

    MIM cap, MOM cap, PIP cap can be used too.
    It depends on application requirement, like substrate noise.
    MOS varactor can achieve smaller die size in some cases.



  7. #7
    Advanced Member level 1
    Points: 4,310, Level: 15
    Achievements:
    7 years registered

    Join Date
    Jul 2009
    Location
    USA
    Posts
    425
    Helped
    160 / 160
    Points
    4,310
    Level
    15

    Re: Standard Decaps in Industry

    Quote Originally Posted by tasctasc View Post
    Hello,
    Just wondering if anyone is able to tell me what the typical decap structures used in industry look like? Are they generally MOScaps or some other structure? Are the same structures used for whitespace decaps as well as those used within standards cells?
    Thank you in advance :o)
    The application might demand different types of decoupling, decoupling of RF components and current limiting in case of defects tend to require a compromise.

    For an idea of what solutions are common have a look at std cell libraries e.g. ARM in TSMC 65nm has an interesting solution but I am not at liberty to discuss it


    1 members found this post helpful.

  8. #8
    Advanced Member level 4
    Points: 10,068, Level: 24
    leo_o2's Avatar
    Join Date
    Sep 2004
    Location
    China
    Posts
    1,324
    Helped
    278 / 278
    Points
    10,068
    Level
    24

    Re: Standard Decaps in Industry

    Junction capacitor can be used too.



  9. #9
    Full Member level 6
    Points: 5,306, Level: 17

    Join Date
    Mar 2002
    Location
    China
    Posts
    360
    Helped
    16 / 16
    Points
    5,306
    Level
    17

    Re: Standard Decaps in Industry

    When decoupling, pay attention to the root square of the product Lbond x Cdecap with :
    - Lbond = bonding wire inductance
    - Cdecap = decoupling capacitance
    It can resonate with your circuit application frequency anf create a lot of spur in your signals !
    A trick is to add a damping resistor in series with your decoupling capacitors.

    For your culture : Decap usually mean decaping package = opening package



  10. #10
    Member level 1
    Points: 419, Level: 4

    Join Date
    Jul 2011
    Posts
    40
    Helped
    0 / 0
    Points
    419
    Level
    4

    Re: Standard Decaps in Industry

    Thank you leo_02, dgnani and okguy for your responses. Your help is much appreciated.

    Thank you dgnani for directing me to ARM. Unfortunately I do not have access to it. Any hints on whereI can find some information would be appreciated :o) (a paper, presentation, website, etc.) although I realize this may be difficult to come by.

    ---------- Post added at 19:35 ---------- Previous post was at 19:35 ----------

    Also, does anyone know if isolation switches are commonly used with decaps?



    •   AltAdvertisement

        
       

  11. #11
    Newbie level 4
    Points: 103, Level: 1

    Join Date
    Jul 2012
    Posts
    7
    Helped
    0 / 0
    Points
    103
    Level
    1

    Re: Standard Decaps in Industry

    Hello, I am looking for on-chip capacitors with large value to do power delivery unit design. It requires the capacitor can be charged and discharged in a large range like 0 to 1.2 V. And I find MOS cap has a very large capacitance variation cause by Vgate between 0 to 1V. I would like to use MIM cap, but it suffers larger area penalty compared to MOS cap. Do you have any solution for achieving large capacitance density with a acceptable area? Thank you very much.



--[[ ]]--