Ceramic, Tantulum, Electrolytic Cap, which one to be used & when

Hi,

Typically ceramic and tantalum capacitors are used for decoupling and bypass capcitors. These decoplers and bypass caps help to reduce current ripple and niose in certain circuits. Electrolytic are used for bulk capacitance (high values of capacitance), used on output stages of power supplies etc.

Ceramic caps have very low ESR (equivalent series resistance) compared to electrolytic and tant, and electrolytic usually have the highest ESR's. http://en.wikipedia.org/wiki/Equivalent_series_resistance

The cost of each is a factor too. Electolytics are cheap compared to cermics $/Farad

But there are many different applications for each of the different types and some research can be used to find the applications

This is really a question about general electronics - nothing specifically to do with the MSP430

ceramic capacitors have a low ESR and can bear a high voltage. Also, their capacitance doesn't change depending on frequency and voltage (on a high ESR, the ESR forms a low pass filter with the capacitance, so from outside, the capacitance seems to drop with frequency). They don't have a polarity.
The drawback is the large size copmare with capacitance, and the large tolerance except for the NP0 dielectricum (which in turn is even larger, allowing onlöy even smaller capacitances).

Electrolytic capacitors have a large capacitance on small volume and can be produced for higher voltages too (with increasing size). However, their ESR is very large, they age due to to loss of electrolyte and they usually have a large leakage current. Also, they do have a polarity (even though there are version available without ploarity - at the cost of additional size and price)

Tantalum capacitors are in the middle. They have a relatively high ESR (but lower than standard electrolytic capacitors) and are immediately destroyed when their nominal voltage is exceeded (which isn't very high too, usually 10V or less). Their advantage is the high capacitance while there is almost no leakage current.
The high ESR does not make them very good for filtering high frequencies, but the capacitance is good for lower frequencies. Therefore they are often combined wiht ceramic capacitors which make up for high frequency filtering but do not have enough capacitance to equalize lower frequency distortions.

A typical combo is 10µF Tantalum with 100nF ceramic. It is recommended for blocking noise on teh analog voltage supply pins or the external reference on the MSPs.