User talk:Bobosoft

In regards to the question, "Is the following statement true?" 'Their [tantalum capacitors] effective series resistance (ESR) is quite high when compared to aluminum electrolytic capacitors.'

I got a response from a senior engineer at AVX Corporation, one of the world's premier tantalum capacitor suppliers, as follows:

Large aluminum electrolytic capacitors do have low ESR just due to their large physical size, but then they will also have a large ESL due to the self inductance from such large windings. The effect is then to actually suppress the delivery of charge so the low ESR is ineffectual.

If we compare two capacitors of the same capacitance, say a popular 100uF, then the aluminum would be substantially larger, a poor form factor for surface mounting, have a limited life and the ESR about 10x that of the smaller, surface mount friendly tantalum part - particularly the conductive polymer version.

Indeed, a bench study we carried out for customers wishing to replace bulky, unreliable, poor performing aluminum electrolytic caps showed that due to the lower ESR and ESL of the tantalum we could replace their capacitance on a 1:5 to 1:10 ratio; that is, a 10uF tantalum had the same or better filtering performance as a 100uF aluminum.

Another factor is the change of ESR over temperature. Being a solid electrolytic the tantalum operates over an extreme temperature range, whereas the Al type with a 'wet' or water based electrolyte has hugely increasing ESR with low temperatures.