Hi,
I have been looking into using Oscons to replace power filters in digital circuits, but after reading the Sanyo warnings page for oscons they warn about very hugh initial charge, and post turn off discharge rates. (Due to the very low esr of oscons)
I am wondering if anyone has experience with going overboard in swapping out regular smd electrolytics for oscons? (I know a lot of DIYers live by the motto Bigger is always better, but it seems just to replace with the ssame value oscon could really damage a chip/circuit.
You can get the operating precautions info by clicking the link on the following page and down loading the .pdf titled operating precautions (Or you can download the entire line info {2.1MB} for more complete explaination of inpact of using oscon
http://www.secc.co.jp/english/products/capacitor/oscon/download.html
Thanks for your thoughts.
God bless...
Mark
I have been looking into using Oscons to replace power filters in digital circuits, but after reading the Sanyo warnings page for oscons they warn about very hugh initial charge, and post turn off discharge rates. (Due to the very low esr of oscons)
I am wondering if anyone has experience with going overboard in swapping out regular smd electrolytics for oscons? (I know a lot of DIYers live by the motto Bigger is always better, but it seems just to replace with the ssame value oscon could really damage a chip/circuit.
You can get the operating precautions info by clicking the link on the following page and down loading the .pdf titled operating precautions (Or you can download the entire line info {2.1MB} for more complete explaination of inpact of using oscon
http://www.secc.co.jp/english/products/capacitor/oscon/download.html
Thanks for your thoughts.
God bless...
Mark
Htguy said:
Hi.
I read on another thread recently (posted by Elso - I think) that Oscons and other very low ESR caps should not be used at the output of regulators, presumably because of the inrush current. At switch-on, the cap would appear as a dead short !!!
Reading the pdf files, it would also appear that problems could occur if an Oscon was parallelled with other caps as smoothing, pre-regulator, since they would 'grab' the lion's share of the ripple !
So, my reading of the situation is as follows :-
Oscons should only be used in low ripple current circuits.
Oscons should not be used immediately post regulator, unless a slow startup is used.
Which does lead to the question :-
where should they be used?
Andy
Hi,
I haven't read the Oscon 'reference', but I think you will find that the advice not to use Oscons directly at the outputs of some regulators is (usually) for an entirely different reason.
Because of their extremely low ESR at HF, it is often recommended to add a low-value resistor in series with the output cap, to help prevent any potential oscillation which could otherwise occur.
The biggest problem I found with Oscons, and I did use quite a few some years ago, is their very low voltage ratings generally, IIRC with about 25v max. here.
It may be that some users have attempted to go beyond the safe usable voltages, as this would very likely cause some problems in use, and manufacturers will always tend to err on the side of caution as they naturally don't want any 'come-backs'.
Blackgates have even lower ESRs, and I have never experienced any problems in use with these. Incidentally, good regulator designs will usually have some diodes (or will recommend using these) to avoid the output caps from discharging back through the regs at switch-off, but it is dangerous to assume this without checking.
Regards,
I haven't read the Oscon 'reference', but I think you will find that the advice not to use Oscons directly at the outputs of some regulators is (usually) for an entirely different reason.
Because of their extremely low ESR at HF, it is often recommended to add a low-value resistor in series with the output cap, to help prevent any potential oscillation which could otherwise occur.
The biggest problem I found with Oscons, and I did use quite a few some years ago, is their very low voltage ratings generally, IIRC with about 25v max. here.
It may be that some users have attempted to go beyond the safe usable voltages, as this would very likely cause some problems in use, and manufacturers will always tend to err on the side of caution as they naturally don't want any 'come-backs'.
Blackgates have even lower ESRs, and I have never experienced any problems in use with these. Incidentally, good regulator designs will usually have some diodes (or will recommend using these) to avoid the output caps from discharging back through the regs at switch-off, but it is dangerous to assume this without checking.
Regards,
Bobken said:Hi,
I haven't read the Oscon 'reference', but I think you will find that the advice not to use Oscons directly at the outputs of some regulators is (usually) for an entirely different reason.
Because of their extremely low ESR at HF, it is often recommended to add a low-value resistor in series with the output cap, to help prevent any potential oscillation which could otherwise occur.
Regards,
I agree with bobken. It's not an inrush current problem.
Bobken said:Hi,
I haven't read the Oscon 'reference', but I think you will find that the advice not to use Oscons directly at the outputs of some regulators is (usually) for an entirely different reason.
Because of their extremely low ESR at HF, it is often recommended to add a low-value resistor in series with the output cap, to help prevent any potential oscillation which could otherwise occur.
The biggest problem I found with Oscons, and I did use quite a few some years ago, is their very low voltage ratings generally, IIRC with about 25v max. here.
It may be that some users have attempted to go beyond the safe usable voltages, as this would very likely cause some problems in use, and manufacturers will always tend to err on the side of caution as they naturally don't want any 'come-backs'.
Blackgates have even lower ESRs, and I have never experienced any problems in use with these. Incidentally, good regulator designs will usually have some diodes (or will recommend using these) to avoid the output caps from discharging back through the regs at switch-off, but it is dangerous to assume this without checking.
Regards,
I can see that a low value resistor would damp oscillations but whats the point in using a low ESR capacitor and then adding resistance ?
Hi,
Regrettably, I have thrown out all of my data on Cerafines and Oscons, as I no longer use these caps out of choice. Having used them (and Silmics) for many years, I am familiar with their general characteristics in use, though. I am sure there must be lot of info. on the 'net, if you do some searches on this subject.
Without spending hours in research, all I can quickly find on Blackgates is the following, which is not very spectacular, it must be said. Jelmax claim 156 mOhm with a pair of 220uF x 6v3 BGNXs at 100kHz, used in their recommended "Super 'E' configuration".
However from several graphs which I have seen, what was more significant was that the BG ESR graphs continued downwards in an almost linear fashion, all the way up to 1Mhz. Others I have seen will inevitably 'turn back' at some point, possibly well prior to 100kHz even, and the curve shoots back upwards at VHF to very much higher figures again.
Whether these figures can be believed, I will not speculate as there have been too many arguments on the Forum in the past about this subject. I have never measured any caps' ESR for myself.
If it helps, I used to use Cerafines for many years, all over the place, and 'subjectively' found them to be good. Later on, when Oscons became available, I found these to be better in certain situations (especially digital), and then later still, I tried BGs, which were (generally) even better than Oscons in analogue circuits, and most digital locations too. I don't wish to say any more about this as it has been such a contentious subject before, but I would not choose to go back to previously-used types of caps, nowadays.
From your query's point of view, though, I have never (yet!) experienced any problems along the lines of your initial concerns, and I have been 'swapping' components for some 35 yrs. now, in every audio location (analogue and later on in digital circuits) you can imagine.
IHTH.
Regards,
Edit: Maybe I should have said that I have needed to replace diode bridges on occasions, due to the higher initial inrush current at start-up with using both lower ESR caps, and using increased values of caps here.
Regrettably, I have thrown out all of my data on Cerafines and Oscons, as I no longer use these caps out of choice. Having used them (and Silmics) for many years, I am familiar with their general characteristics in use, though. I am sure there must be lot of info. on the 'net, if you do some searches on this subject.
Without spending hours in research, all I can quickly find on Blackgates is the following, which is not very spectacular, it must be said. Jelmax claim 156 mOhm with a pair of 220uF x 6v3 BGNXs at 100kHz, used in their recommended "Super 'E' configuration".
However from several graphs which I have seen, what was more significant was that the BG ESR graphs continued downwards in an almost linear fashion, all the way up to 1Mhz. Others I have seen will inevitably 'turn back' at some point, possibly well prior to 100kHz even, and the curve shoots back upwards at VHF to very much higher figures again.
Whether these figures can be believed, I will not speculate as there have been too many arguments on the Forum in the past about this subject. I have never measured any caps' ESR for myself.
If it helps, I used to use Cerafines for many years, all over the place, and 'subjectively' found them to be good. Later on, when Oscons became available, I found these to be better in certain situations (especially digital), and then later still, I tried BGs, which were (generally) even better than Oscons in analogue circuits, and most digital locations too. I don't wish to say any more about this as it has been such a contentious subject before, but I would not choose to go back to previously-used types of caps, nowadays.
From your query's point of view, though, I have never (yet!) experienced any problems along the lines of your initial concerns, and I have been 'swapping' components for some 35 yrs. now, in every audio location (analogue and later on in digital circuits) you can imagine.
IHTH.
Regards,
Edit: Maybe I should have said that I have needed to replace diode bridges on occasions, due to the higher initial inrush current at start-up with using both lower ESR caps, and using increased values of caps here.
If you want to install an oscon following a regulator, bring up the datasheet for the regulator in question and look for a stability vs capacitance/ESR plot. If it won't work, you should change out the regulator. Don't worry about inrush, the great majority of regulators out there have short circuit protection.
Most standard/NPN regulators (78xx, etc) i've seen can be happy with extremely small ESR's on their output, but LDO (PNP) regulators can be far more fussy. I've got a tendency to design paralleled 10uF/25V and 47uF/6.3V ceramics into things, which makes for extremely solid rails but makes the selection of regulators extremely tough.
Most standard/NPN regulators (78xx, etc) i've seen can be happy with extremely small ESR's on their output, but LDO (PNP) regulators can be far more fussy. I've got a tendency to design paralleled 10uF/25V and 47uF/6.3V ceramics into things, which makes for extremely solid rails but makes the selection of regulators extremely tough.
Hi,
Thanks for all the input guys. Bobken, I am not trying to stir up trouble, but if you get a change if you could take a look at this link to an o-scop compairison of oscon, cerafine and BG caps. His conclusions (for digital use) are different from your and I wonder if there is something he is missing that explains your experience?
Anyone have any thoughts as to the validity of the findings on oscon vs cerafine vs BG?
http://diyparadise.com/cap/dare_to_compare.html
God bless...
Mark
Thanks for all the input guys. Bobken, I am not trying to stir up trouble, but if you get a change if you could take a look at this link to an o-scop compairison of oscon, cerafine and BG caps. His conclusions (for digital use) are different from your and I wonder if there is something he is missing that explains your experience?
Anyone have any thoughts as to the validity of the findings on oscon vs cerafine vs BG?
http://diyparadise.com/cap/dare_to_compare.html
God bless...
Mark
Hi Mark,
I really don't wish to protract this discussion, as 'we have been there' on this Forum, many times before. If you are sufficiently interested, there have been many threads on the subject of comparing different caps., as a search should reveal.
With respect, it is nothing to do with your original query, which I answered truthfully and comprehensively, and I even covered the point which a subsequent poster mentioned, as this was unfortunately (and I am sure quite inadvertently) misleading here. I was sorry to see that this did not appear to satisfy you entirely, and I also mentioned I preferred not to comment any further because of the likely outcome.
I didn't say that every BG exhibited a lower ESR than every other cap, and I did imply that oscons were 'subjectively' good in digital circuits, IME. I even acknowledged that the only quick example I could find was not very impressive in this ESR measurement of BGs.
I Quote:
" Oscons... certain situations...better... *especially digital*.... and BGs...generally...better than Oscons in *analogue circuits*... and *most* digital locations".
I did mention that I had not measured any caps' *ESR*, and that my conclusions were formed empirically, but I don't see any real conflict between my findings, anyway, and what is shown on the site you now refer to. As I am not especially concerned about what someone else has shown there, I only very briefly looked at what was shown on that site, merely as a courtesy to you, and as you had requested this. However, I did not see anything there which indicated the ESR measurements of any caps, unfortunately, but perhaps I missed this in my haste.
For brevity (and as it did not form part of the question), I did not differentiate between the different locations in which caps are used. i.e. PS smoothing, or signal-coupling, or whatever, and different choices here for different locations will provide the best subjective results, in my experience. Here it is not necessarily the same for digital signals and analogue, as we are often dealing with different frequencies and amplitudes etc.
There are 9 different types of BG caps, but again originally for brevity, I avoided commenting on this, but the Standard Series which the tester used in your reference (which can be clearly identified from his pic.) is not a series I would use at all. I have posted several times on this Forum before, that the Standard BGs are not better in any way (IME) than many other caps, including Elnas and Oscons.
Personally, I only find the non-polar BGs (N,NX, NXHQ) to be worthwhile using (as I have also posted several times before) and they are excellent (IMO), subjectively, in most locations, although I detest their ridiculous cost. According to Jelmax, these non-polar series all measure differently from each other, and are considerably better (generally) than their Standard Series, by design. I won't comment on any claimed measurements, but I (and many others who have put this to the test) have found that their claims are generally reflected when carrying out 'listening' tests on these products.
Actually, the only reason for mentioning *any* other caps, myself, was merely to indicate that these 'substitution trials' you had queried with various different caps, were quite 'safe' (IME) whatever cap I have tried, and however low their ESRs happen to be.
Please, could you now accept that I attempted to assist you by alleviating any concerns which you originally expressed in your initial post, by advising that the issue you raised is not of any practical consequence (IME) with any cap of even very low ESR, when the suggested substitutions are contemplated?
Have a good weekend.
Regards,
I really don't wish to protract this discussion, as 'we have been there' on this Forum, many times before. If you are sufficiently interested, there have been many threads on the subject of comparing different caps., as a search should reveal.
With respect, it is nothing to do with your original query, which I answered truthfully and comprehensively, and I even covered the point which a subsequent poster mentioned, as this was unfortunately (and I am sure quite inadvertently) misleading here. I was sorry to see that this did not appear to satisfy you entirely, and I also mentioned I preferred not to comment any further because of the likely outcome.
I didn't say that every BG exhibited a lower ESR than every other cap, and I did imply that oscons were 'subjectively' good in digital circuits, IME. I even acknowledged that the only quick example I could find was not very impressive in this ESR measurement of BGs.
I Quote:
" Oscons... certain situations...better... *especially digital*.... and BGs...generally...better than Oscons in *analogue circuits*... and *most* digital locations".
I did mention that I had not measured any caps' *ESR*, and that my conclusions were formed empirically, but I don't see any real conflict between my findings, anyway, and what is shown on the site you now refer to. As I am not especially concerned about what someone else has shown there, I only very briefly looked at what was shown on that site, merely as a courtesy to you, and as you had requested this. However, I did not see anything there which indicated the ESR measurements of any caps, unfortunately, but perhaps I missed this in my haste.
For brevity (and as it did not form part of the question), I did not differentiate between the different locations in which caps are used. i.e. PS smoothing, or signal-coupling, or whatever, and different choices here for different locations will provide the best subjective results, in my experience. Here it is not necessarily the same for digital signals and analogue, as we are often dealing with different frequencies and amplitudes etc.
There are 9 different types of BG caps, but again originally for brevity, I avoided commenting on this, but the Standard Series which the tester used in your reference (which can be clearly identified from his pic.) is not a series I would use at all. I have posted several times on this Forum before, that the Standard BGs are not better in any way (IME) than many other caps, including Elnas and Oscons.
Personally, I only find the non-polar BGs (N,NX, NXHQ) to be worthwhile using (as I have also posted several times before) and they are excellent (IMO), subjectively, in most locations, although I detest their ridiculous cost. According to Jelmax, these non-polar series all measure differently from each other, and are considerably better (generally) than their Standard Series, by design. I won't comment on any claimed measurements, but I (and many others who have put this to the test) have found that their claims are generally reflected when carrying out 'listening' tests on these products.
Actually, the only reason for mentioning *any* other caps, myself, was merely to indicate that these 'substitution trials' you had queried with various different caps, were quite 'safe' (IME) whatever cap I have tried, and however low their ESRs happen to be.
Please, could you now accept that I attempted to assist you by alleviating any concerns which you originally expressed in your initial post, by advising that the issue you raised is not of any practical consequence (IME) with any cap of even very low ESR, when the suggested substitutions are contemplated?
Have a good weekend.
Regards,
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