Low ESR electrolytic service life query
- Thread starter BrendanP
- Start date
Yup.
I think it's something like double-the-life for every 10 degrees below rated value.. or something like that.
Remember, the temperature relates to internal temp and this is affected by how much ripple you chuck through at whatever voltage.
To save space, check this out...
http://www.svalander.se/shoppen/pdf/electrolytic_life_factors.pdf
P.S. There are gallons of articles on electrolytic capacitors on net.
I think it's something like double-the-life for every 10 degrees below rated value.. or something like that.
Remember, the temperature relates to internal temp and this is affected by how much ripple you chuck through at whatever voltage.
To save space, check this out...
http://www.svalander.se/shoppen/pdf/electrolytic_life_factors.pdf
P.S. There are gallons of articles on electrolytic capacitors on net.
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BeanieBots
Moderator
Works the other way too. If your product is to be sold from Beijing, run it at 63v. Should last long enough to get through QC and then fail within a few days with the customer
My golden rule with electrolytics is never exceed 1/2 the spec voltage and/or ripple current. For high ripple currents it is better to fit two or more smaller caps than one large one.
My golden rule with electrolytics is never exceed 1/2 the spec voltage and/or ripple current. For high ripple currents it is better to fit two or more smaller caps than one large one.
You need to be a little careful when running electrolytics at voltages much lower than rated, because they need polarisation to work. I don't know the actual numbers but to me running a high value 50v cap at 3.6v seems to be asking for trouble, as well as costing far more for the part than necessary. The dielectric oxide film in an electrolytic cap is maintained by the leakage current, which may not be enough if run all the time at well below the rated voltage.
I would take a look at the manufacturer's spec, if you can find it.
I would take a look at the manufacturer's spec, if you can find it.
Thanks for the replys. I know nothing of the intricacies of cap. selection. I will go read the link suggested after posting.
I was going to use the AFK108M50P44T whose data sheet is here:
http://www.cde.com/catalogs/AFK.pdf
I intend to use the cap. as part of a the power supply of a GSM module. The GSM module needs the cap. because it draws up to 2 amps instaneously during bursts of data txing. The cap. is to provide a 'reservoir' to ensure there is no voltage drop during these bursts. V drop will lead to malfunction, so says the manufacuters manuals. Said manuals say to use the biggest cap. you can, 1000uf or larger located as close as possible to the module.
I have several protos pcb Ive designed with the module functioning on them. Im now drawing up another smaller board and as Im trying to stuff the whole design into a much smaller package Im looking at smd parts like the cap above.
Is there any advantage to using a higher voltage rate cap. at all. I saw a note in the mouser catalogue that said you can use a higher rated cap in a smaller V circuit.
Would I be better off using a 6.3V/ 6800uf cap? (The GSM module is running on 3.6V's).
Its in the same package as the 50V part.
I was going to use the AFK108M50P44T whose data sheet is here:
http://www.cde.com/catalogs/AFK.pdf
I intend to use the cap. as part of a the power supply of a GSM module. The GSM module needs the cap. because it draws up to 2 amps instaneously during bursts of data txing. The cap. is to provide a 'reservoir' to ensure there is no voltage drop during these bursts. V drop will lead to malfunction, so says the manufacuters manuals. Said manuals say to use the biggest cap. you can, 1000uf or larger located as close as possible to the module.
I have several protos pcb Ive designed with the module functioning on them. Im now drawing up another smaller board and as Im trying to stuff the whole design into a much smaller package Im looking at smd parts like the cap above.
Is there any advantage to using a higher voltage rate cap. at all. I saw a note in the mouser catalogue that said you can use a higher rated cap in a smaller V circuit.
Would I be better off using a 6.3V/ 6800uf cap? (The GSM module is running on 3.6V's).
Its in the same package as the 50V part.
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