MLCC capacitors do indeed decrease capacitance a fair amount as you increase the DC bias. As an example, I've used some 1210 size, 100V 2.2uF MLCC caps which, at 50V, show only about 1.6uF capacitance. I think these have X5R dielectric. I don't think that they mean that a 100uF MLCC can exactly replace a 470uF Tantalum cap. They mean that, in many circuits, a 470uF tantalum is often spec'd to get a certain minimum ESR and a lower capacitance could be acceptable if the ESR were low enough. A 100uF MLCC could easily have only 5 milliohm ESR, which is about 10x lower than a similarly-sized Tantalum. Sean On Mon, Feb 22, 2010 at 4:17 PM, Funny NYPD wrote: > Check out page 11 of 16 in the following presentation (Breakdown voltage = comparison): > http://dkc1.digikey.com/ca/en/tod/Murata/HighCapMultiCeramicCap/HighCap_M= ultilayer_Ceramic_Caps.html > > On page 12 of 16, it claims the cap is heavily affected by DC bias voltag= e. > > On the last page, one summary is: a 100UF MLCC ceramic cap can replace 47= 0 uf Tan cap. > > > =A0Funny N. > Au Group Electronics, http://www.AuElectronics.com > http://www.AuElectronics.com/products > http://augroups.blogspot.com/ > > > > > ________________________________ > From: Herbert Graf > To: Microcontroller discussion list - Public. > Sent: Mon, February 22, 2010 3:36:54 PM > Subject: Re: [EE]Overvoltage on Ceramic Capacitors. > > On Mon, 2010-02-22 at 11:06 -0800, Marcel Duchamp wrote: >> On 2/22/2010 10:52 AM, Funny NYPD wrote: >> > For =A0most of the electrolytic capacitor, they cannot be used =A0when >> > application voltage is higher than the rated voltage. For ceramic >> > Capacitors, they won't be damaged if the application voltage is >> > higher but doesn't go above 1K Volts~a few Kilo-volts. >> > >> >> Where did you get that idea? =A0Voltage ratings are not "optional"... > > Agreed. Perhaps what he was referring to is ceramic caps are more > "forgiving" if you get close to the max. Tantalums tend to explode > pretty much right at their rated maximum. > > TTYL > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist