how to use tantalum capacitor?

[huzuhong525]

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

 

[RF-OM]

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

 

[huzuhong525]

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 ?

 

[s.san2006]

tantalum cap polarity

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

 

[svicent]

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.

 

[Borber]

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.

 

[max0412]

how to use capacitor

Everything you wanted to know about caps.

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.

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.

 

[Medini]

tant caps polarity

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

 

[huzuhong525]

polarity of tantalum capacitor

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

 

[tyassin]

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