+ Post New Thread
Results 1 to 10 of 10
  1. #1
    Junior Member level 2
    Points: 1,161, Level: 7

    Join Date
    Jun 2008
    Location
    China
    Posts
    22
    Helped
    3 / 3
    Points
    1,161
    Level
    7

    tantalum capacitor polarity

    hi ,
    I am a new to electric design ,could somebody list how to use tantalum capacitor or tantalum capacitor used where,the difference from MLCC &other capacitor ?

    thank you

  2. #2
    Advanced Member level 2
    Points: 6,883, Level: 19

    Join Date
    Aug 2007
    Location
    The Earth
    Posts
    584
    Helped
    127 / 127
    Points
    6,883
    Level
    19

    tantalum capacitors polarity

    Tantalum capacitors are electrolytic type. They have big capacitance for relatively small size, the best Farad-per-volume-unit ratio and this is the best type of electrolytic caps, but most expensive one. They are kind of low frequency devices. When you use electrolytic caps you need to keep in mind that they are polarized and therefore must be connected according to their polarity. MLCC or Multi-Layer Ceramic Capacitors are high quality caps. They are able to work on high frequencies (depends on dielectric type). They may be very small and use in high frequency electronics, RF and microwave circuits. The major parameters are capacitance, ESR (Equivalent Series Resistance), ESL (Equivalent Series Inductance), SRF (self-resonant frequency), and Q-factor. Capacitance is ability to store an electrical field energy and this is what we need; next two parameters are parasitic. They reduce upper usable frequency of capacitor as well as Q-factor. The latter shows how much energy will lost into cap, but usually Q is not the problem for capacitors. What is important to know it is what the actual capacitance is. For majority of practical applications this parameter can be calculated as Ceff=C/(1-f/SRF)^2. Here f is frequency of interest and SRF is self-resonant frequency from the data sheet. This formula assumes that cap is used well below the SRF. It is easy to see that very often we have much higher capacitance than shown on the cap itself. Even when when we use cap on frequency about half of SRF the effective capacitance Ceff will be 4 times higher than expected.

    Best regards,
    RF-OM



  3. #3
    Junior Member level 2
    Points: 1,161, Level: 7

    Join Date
    Jun 2008
    Location
    China
    Posts
    22
    Helped
    3 / 3
    Points
    1,161
    Level
    7

    tantalum polarity

    Thanks .

    In our GPS project ,the audio singal comes through a 100uf tantalum capacitor that is coupling function,may i use MLCC to replace it for coupling ?



  4. #4
    Newbie level 6
    Points: 910, Level: 6

    Join Date
    Mar 2008
    Posts
    12
    Helped
    0 / 0
    Points
    910
    Level
    6

    tantalum cap polarity

    Similar to an electrolytic cap, but with good reliability, but blows up badly if connected with wrong polarity.



  5. #5
    Full Member level 6
    Points: 6,652, Level: 19

    Join Date
    Jul 2001
    Posts
    322
    Helped
    32 / 32
    Points
    6,652
    Level
    19

    smd tantalum capacitor polarity

    A major advantage of tantalum capacitors is that they can be packaged in much smaller sizes than aluminium electrolytics. This means that they are better suited to surface mount production and indeed the majority of small surface mount electrolytics are tantalum types. Capacitance values from 0.1μF to 470μF are available.



  6. #6
    Advanced Member level 4
    Points: 16,781, Level: 31
    Borber's Avatar
    Join Date
    Dec 1999
    Location
    on third flor
    Posts
    1,405
    Helped
    184 / 184
    Points
    16,781
    Level
    31

    capacitor tantalum polarity

    One of the advantages of tantalum over aluminium electrolytes is much smaller leakage current. This is important when capacitor interstage coupling is used.



  7. #7
    Full Member level 5
    Points: 3,662, Level: 14

    Join Date
    Oct 2003
    Posts
    253
    Helped
    37 / 37
    Points
    3,662
    Level
    14

    how to use capacitor

    Everything you wanted to know about caps.

    Code:
    http://www.radio-electronics.com/info/data/capacitor/capacitor_types.php
    AVX application notes. If your planning on using Tant caps I suggest you read through these notes from AVX.

    I used tinyurl to shorten AVX's 232 character url to the page.

    Code:
    http://tinyurl.com/3ttzys
    Particularly

    Voltage Derating Rules for Solid Tantalum & Niobium Capacitors

    and

    Surge in Solid Tantalum Capacitors

    and

    Ripple Rating of Tantalum Chip Capacitors

    and

    Increasing Reliability of SMD Tantalum Capacitors in Low Impedance Applications

    Most of the notes are worth looking through but those are the minumum.


    1 members found this post helpful.

  8. #8
    Newbie level 5
    Points: 845, Level: 6

    Join Date
    Jun 2008
    Posts
    10
    Helped
    0 / 0
    Points
    845
    Level
    6

    tant caps polarity

    Be careful the max voltage change with temperature and they blow easily. If you can, use ceramic or aluminum



  9. #9
    Junior Member level 2
    Points: 1,161, Level: 7

    Join Date
    Jun 2008
    Location
    China
    Posts
    22
    Helped
    3 / 3
    Points
    1,161
    Level
    7

    polarity of tantalum capacitor

    Thanks for your kind help ,I got much from you .



  10. #10
    Advanced Member level 1
    Points: 6,289, Level: 18

    Join Date
    Jul 2004
    Posts
    428
    Helped
    75 / 75
    Points
    6,289
    Level
    18

    reliability over voltage tantalum capacitors

    Hi

    You can also use POSCAP or OS_CON. These are have the same features as Tantalum but are much more robust too surges and over voltage.

    Regards