Capacitor ESR ??

Jim Thompson · Feb 11, 2004

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice

480)460-2350 | |
| E-mail Address at Website Fax

James Beck · Feb 11, 2004

In article <tp1l20dnivs12k650mkvvehv8961vh2cd0@4ax.com>,
thegreatone@example.com says...

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

I did a quick look at some of our suppliers websites and I think this
has some references to Al Cap ESR in it.

http://www.nichicon.com/english/lib/alminium.pdf

Jim

Rene Tschaggelar · Feb 11, 2004

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

The ESR is a matter of technology.
Have a look at the manufacturer's pages, eg
http://www.epcos.com

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

Jim Thompson · Feb 11, 2004

On Wed, 11 Feb 2004 19:58:17 GMT, James Beck
<jim@reallykillersystems_INVALID_.com> wrote:

In article <tp1l20dnivs12k650mkvvehv8961vh2cd0@4ax.com>,
thegreatone@example.com says...
I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

I did a quick look at some of our suppliers websites and I think this
has some references to Al Cap ESR in it.

http://www.nichicon.com/english/lib/alminium.pdf

Jim

480)460-2350 | |
| E-mail Address at Website Fax

Andreas Hadler · Feb 11, 2004

Jim Thompson <thegreatone@example.com> wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Just look up in LTspice's capacitor list to see what
voltage/capacity/ESR ranges are viable?

aha
--
"Computers are useless. They can only give you answers."
-Pablo Picasso

Mike Rocket J. Squirrel E · Feb 11, 2004

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)

Jim Thompson · Feb 11, 2004

On Wed, 11 Feb 2004 15:22:29 -0800, "Mike Rocket J. Squirrel Elliott"
<j.michael.elliottAT@REMOVETHEOBVIOUSadelphiaDOT.net> wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

480)460-2350 | |
| E-mail Address at Website Fax

Mike Rocket J. Squirrel E · Feb 12, 2004

Jim Thompson wrote:

On Wed, 11 Feb 2004 15:22:29 -0800, "Mike Rocket J. Squirrel Elliott"
j.michael.elliottAT@REMOVETHEOBVIOUSadelphiaDOT.net> wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

Wouldn't that mean you need DF given at a specific frequency so that
you can work back to ESR (which should(?) be fairly constant)?

At 0Hz, the ESR of a capacitor will be darn high. It drops as one goes
up in frequency until inductance takes over.

When you do find specs for ESR in capacitor data sheets, they specify at
which frequency (usually 120Hz in the US) they are providing the ESR for.

According to
http://www.cooltron.com/component/technical/library_of_capacitor.shtml

7. Equivalent Series Resistance (ESR)

It's the sum of all the internal resistances of a capacitor measured in
Ohms. It includes:

- Resistance due to aluminum oxide thickness
- Resistance due to electrolyte / spacer combination
- Resistance due to materials (Foil length; Tabbing; Lead wires; Ohmic
contact resistance)

The lower the ESR the higher the current carrying ability the capacitor
will have. The amount of heat generated by ripple current depends upon
the ESR of the capacitor.

ESR is both frequency and temperature dependent, increasing either will
cause a reduction in ESR. The ESR is an important parameter in
calculating life expectancy as the power dissipation (internally
generated heat) is directly proportional to its value.

--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)

John Popelish · Feb 12, 2004

"Mike Rocket J. Squirrel Elliott" wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

I think dissipation factor includes several factors, one of which is
ESR. The bigger factor at higher frequencies is a fairly constant per
cycle loss. Your formula looks like it is interpreting those per
cycle losses as ESR. Not very useful, I suspect.

--
John Popelish

Martin Riddle · Feb 12, 2004

Have you tried www.kemet.com , their AO-CAP alum. caps have ESR@100k ~25-15 mohm.
For Tants see the 'Solid Tant Chip Performance characteristics'. Here is where DF=ESR/Xc=2xPIxFxCxR

They also have a spice manual.
Have fun

"Jim Thompson" <thegreatone@example.com> wrote in message news:tp1l20dnivs12k650mkvvehv8961vh2cd0@4ax.com...

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Mike Rocket J. Squirrel E · Feb 12, 2004

John Popelish wrote:

"Mike Rocket J. Squirrel Elliott" wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

I think dissipation factor includes several factors, one of which is
ESR. The bigger factor at higher frequencies is a fairly constant per
cycle loss. Your formula looks like it is interpreting those per
cycle losses as ESR. Not very useful, I suspect.

You may be right. My formula was provided by the engineer at ASC, and
I've also seen it on some online sites as well. I'll bet that the
formula is useful for line-frequency based power supplies, though.

--
Mike "Rocket J Squirrel" Elliott
71 VW Type 2 -- the Wonderbus (AKA the Saunabus in summer)

qrk · Feb 12, 2004

On Wed, 11 Feb 2004 16:55:09 -0700, Jim Thompson
<thegreatone@example.com> wrote:

On Wed, 11 Feb 2004 15:22:29 -0800, "Mike Rocket J. Squirrel Elliott"
j.michael.elliottAT@REMOVETHEOBVIOUSadelphiaDOT.net> wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

Wouldn't that mean you need DF given at a specific frequency so that
you can work back to ESR (which should(?) be fairly constant)?

...Jim Thompson

Jim, if you tell me what style capacitor (el cheapo, low-esr, ...), I
might be able to measure the Z on our network analyzer. Z data varies
quite a bit depending on capacitor construction. ESR can vary quite a
bit over frequency, perhaps over 100 to 1 for some ceramic caps (as
reported by AVX's SpiCap program.

FYI, AVX <http://www.avxcorp.com/ProdInfo_Listing.asp> has good data
on their ceramic and tantalum caps.
Aloha, Mark

Leeper · Feb 12, 2004

I've tried some of these AO caps, the A700 series, and one
nice thing, unlike alot of tantalums and some niobium, is they
don't go up in flames....ran a 4V version to 14V and held it
there, and then back down, it nearly recovered all its original
characteristics.

"Martin Riddle" <martinriddle@hotmail.com> wrote in message
news:OQCWb.894$WW3.497@newsread2.news.pas.earthlink.net...

Have you tried www.kemet.com , their AO-CAP alum. caps have ESR@100k
~25-15 mohm.
For Tants see the 'Solid Tant Chip Performance characteristics'. Here is
where DF=ESR/Xc=2xPIxFxCxR

They also have a spice manual.
Have fun

"Jim Thompson" <thegreatone@example.com> wrote in message
news:tp1l20dnivs12k650mkvvehv8961vh2cd0@4ax.com...
I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

Jamie · Feb 12, 2004

Hmm, that looks so much like our Q-factor specs that we
perform for our Mill Spec Mica Dips. and D40's etc.

At least that is what we do at Semco.

Jim Thompson wrote:

On Wed, 11 Feb 2004 15:22:29 -0800, "Mike Rocket J. Squirrel Elliott"
j.michael.elliottAT@REMOVETHEOBVIOUSadelphiaDOT.net> wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

Wouldn't that mean you need DF given at a specific frequency so that
you can work back to ESR (which should(?) be fairly constant)?

...Jim Thompson

Fred Bloggs · Feb 12, 2004

John Popelish wrote:

"Mike Rocket J. Squirrel Elliott" wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

I think dissipation factor includes several factors, one of which is
ESR. The bigger factor at higher frequencies is a fairly constant per
cycle loss. Your formula looks like it is interpreting those per
cycle losses as ESR. Not very useful, I suspect.

Au contraire- if you look at that so-called formula it is the definition
of DF which is the cotangent of the impedance angle of a simple series
R-C equivalent circuit. The DF being small allows the identity between
ratio and tangent function. The small in-phase component of voltage with
current is exactly that fraction of the VA producing dissipated versus
stored energy per cycle and is the equivalent resistance at the
measurement conditions, where resistance is abstracted from being just a
chunk material of finite conductivity to an energy-to-heat conversion
element. It will be non-linear, a functional dependence on temperature,
frequency, and signal level.

DarkMatter · Feb 12, 2004

On Thu, 12 Feb 2004 14:06:57 GMT, Fred Bloggs <nospam@nospam.com> Gave
us:

John Popelish wrote:

I think dissipation factor includes several factors, one of which is
ESR. The bigger factor at higher frequencies is a fairly constant per
cycle loss. Your formula looks like it is interpreting those per
cycle losses as ESR. Not very useful, I suspect.

Au contraire- if you look at that so-called formula it is the definition
of DF which is the cotangent of the impedance angle of a simple series
R-C equivalent circuit. The DF being small allows the identity between
ratio and tangent function. The small in-phase component of voltage with
current is exactly that fraction of the VA producing dissipated versus
stored energy per cycle and is the equivalent resistance at the
measurement conditions, where resistance is abstracted from being just a
chunk material of finite conductivity to an energy-to-heat conversion
element. It will be non-linear, a functional dependence on temperature,
frequency, and signal level.

Nice catch!

John Popelish · Feb 12, 2004

Fred Bloggs wrote:

John Popelish wrote:
"Mike Rocket J. Squirrel Elliott" wrote:

Jim Thompson wrote:

I'm having trouble tracking down typical Capacitor ESR values for
Aluminum and Tantalum electrolytics.

Can someone point me to a page?

Or some rules of thumb I can use in simulations?

Thanks!

...Jim Thompson

Jim,

Capacitor manufacturers no longer like to state ESR, because it depends
on the frequency of interest. As you may have noticed, they do state
Dissipation Factor (DF) instead. I had to do some poking around a few
weeks ago to find the secret formula to convert DF into ESR, and here's
what I learned.

DF/(2*pi*frequency*capacitance) = R

Assume a data sheet DF of .05% And assume you are doing some work at,
say, 1kHz, and the capacitance is, say, 20uF.

So in this instance:

0.0005/(2*3.1416*1000*.000020 = 3.97 milliohms

I think dissipation factor includes several factors, one of which is
ESR. The bigger factor at higher frequencies is a fairly constant per
cycle loss. Your formula looks like it is interpreting those per
cycle losses as ESR. Not very useful, I suspect.

Au contraire- if you look at that so-called formula it is the definition
of DF which is the cotangent of the impedance angle of a simple series
R-C equivalent circuit. The DF being small allows the identity between
ratio and tangent function. The small in-phase component of voltage with
current is exactly that fraction of the VA producing dissipated versus
stored energy per cycle and is the equivalent resistance at the
measurement conditions, where resistance is abstracted from being just a
chunk material of finite conductivity to an energy-to-heat conversion
element. It will be non-linear, a functional dependence on temperature,
frequency, and signal level.

If you want to interpret all losses as if they were a result of an
actual series resistance, and the total losses are low, the formula is
fine. If you want to know what the parallel losses, the series losses
and the hysterisis losses are, it is not much use. I think the best
way to measure the actual series resistance is to subject the cap to
its series resonant frequency and and measure its impedance.
--
John Popelish

Jim Thompson · Feb 12, 2004

On Thu, 12 Feb 2004 18:37:34 -0500, John Popelish <jpopelish@rica.net>
wrote:

[snip]

If you want to interpret all losses as if they were a result of an
actual series resistance, and the total losses are low, the formula is
fine. If you want to know what the parallel losses, the series losses
and the hysterisis losses are, it is not much use. I think the best
way to measure the actual series resistance is to subject the cap to
its series resonant frequency and and measure its impedance.

480)460-2350 | |
| E-mail Address at Website Fax

John Popelish · Feb 13, 2004

Jim Thompson wrote:

On Thu, 12 Feb 2004 18:37:34 -0500, John Popelish <jpopelish@rica.net
wrote:

[snip]
If you want to interpret all losses as if they were a result of an
actual series resistance, and the total losses are low, the formula is
fine. If you want to know what the parallel losses, the series losses
and the hysterisis losses are, it is not much use. I think the best
way to measure the actual series resistance is to subject the cap to
its series resonant frequency and and measure its impedance.

Are you saying that the best model would be a series R-L-C evaluated
at resonance?

Yes. I think ESR shows up most clearly under those conditions.

--
John Popelish

Mike Engelhardt · Feb 13, 2004

Jim,

Are you saying that the best model would be a series
R-L-C evaluated at resonance?

Maybe I should interject here that the equivalent circuit
of an AL electrolytic is really a ladder network:

---/\/\/\---o---/\/\/\---o---/\/\/\---o...
| | |
--+-- --+-- --+--
--+-- --+-- --+--
| | |
------------o------------o------------o...

LTspice's capacitor database just uses 1 R and 1 C
as an quick and effective approximation. But if you
use 2 R's and C's, you can model the phase angle of
the impedance correct within a few degrees over many
decades of freq. Three 3 R's and 3 C's should let
you model more accurately than you can measure with
any component analyzer I know of.

--Mike

Capacitor ESR ??

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