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10uF 50V Low ESR caps
- Thread starter eof1973
- Start date
MacGyverS2000
Electrical
Dan... It is an SMD cap, and it's ceramic.
Q.E.D. Low ESR by definition.
Keith Cress
kcress -
Q.E.D. Low ESR by definition.
Keith Cress
kcress -
To continue: The issue hits when you exceed 22uF and ceramics can no longer provide the required capacitance. Or, for that matter, the voltage requirement goes up too far and drives down the resulting capacitances that are 'ceramic' available.
Keith Cress
kcress -
Keith Cress
kcress -
MacGyverS2000
Electrical
Keith, I guess I was a little too esoteric in my question. I was trying to point out that the OP had not specified a frequency range he desired that ESR at. For example, at 1kHz he'll have a hard time getting an ESR that low, but at 1MHz it won't be an issue. Given that the info was missing, I wanted to know how Hen was able to provide such a certain answer.
Dan - Owner
Dan - Owner
Unfortunately as an EE designing things like switching power supplies the OP will be directed to, "use low ESR caps".
So he won't even have a number.
The general result is, you better find an aluminum electrolytic cap that touts low ESR, or a Tantalum with low ESR, or any ceramic.
Under about 10W, most switching controller IC data sheets are suggesting ceramic caps, (like Henneshoe suggested), stacked on until you reach your capacitance requirement.
Keith Cress
kcress -
So he won't even have a number.
The general result is, you better find an aluminum electrolytic cap that touts low ESR, or a Tantalum with low ESR, or any ceramic.
Under about 10W, most switching controller IC data sheets are suggesting ceramic caps, (like Henneshoe suggested), stacked on until you reach your capacitance requirement.
Keith Cress
kcress -
MacGyverS2000
Electrical
And where did you see the OP was using a switcher or designing a PS? Man, you guys must have extra posts showing up on your screens as you seem to have more info than me... ;-)
Dan - Owner
Dan - Owner
It is just a special sense we have. do, Do, do, do ![[infinity]](/data/assets/smilies/infinity.gif "[infinity] [infinity]")
Also garnered from having to do several switchers in the past year.![[bugeyed]](/data/assets/smilies/bugeyed.gif "[bugeyed] [bugeyed]")
and smelling paint fumes..![[spin2]](/data/assets/smilies/spin2.gif "[spin2] [spin2]")
as I am presently doing.
Keith Cress
kcress -
Also garnered from having to do several switchers in the past year.
and smelling paint fumes..
as I am presently doing.Keith Cress
kcress -
Mac, guess you got me there. These caps do not specify a specific ESR. Guess when I see a spec for a low ESR, I think ceramic unless the capacitance value is too high. Here is the reference I looked at for ESR of X7R when specifying the cap. At 10uf the ESR is around 10mohm. However, they assume <1mhz.
EOF1973, I hope my suggestion still works for your situation, if not, happy hunting.
EOF1973, I hope my suggestion still works for your situation, if not, happy hunting.
MacGyverS2000
Electrical
Hen, not trying to bust your balls, just making sure the OP is aware of what he's asking. I follow the same path you and Keith have mentioned, simply spec'ing a ceramic whenever low ESR is desired (unless some other obvious spec takes precedence). Reels of MLCCs take up quite a bit of shelf space in my work area as I can use them for nearly everything on protos.
Dan - Owner
Dan - Owner
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