Aluminum-Polymer Solid Capacitors

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boji

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Just curious on your opinions about these. Aluminum polys are new to me (maybe best if thread is in brewery).

https://www.mouser.com/new/panasonicec/Panasonic-OSCON-Capacitors

Edit: I see none offered for 'audio grade' use.

Ok, so in low-heat environments, they last longer than lytics:
https://www.we-online.com/web/en/passive_components_custom_magnetics/blog_pbcm/blog_detail_electronics_in_action_105536.php
 
The OSCON series has been around for years. It is targeting low ESR power supply decoupling, like for DC to DC switching PS.

I recall some issues with early low ESR caps failing as a dead short. I suspect they are more reliable now.

JR 
 
Recent datasheets comparisons showed me wet capacitors come in higher voltages and have lower current leakage. Considering low price and quality of better wet capacitors, i still see them as first choice for audio circuits and linear supplies.
A few sources show short as possible failure mode of modern solid polymer types, although they can be very reliable and last longer than wet capacitors.
 
I played with a few maybe a couple of years ago based strictly on their tan theta numbers and longer life than wet electrolytics. I remember getting oscillations using them in a feedback loop (probably due to low ESR?).  I wasn’t able to get them to work in that applicational all. I didn’t find any measurable differences when used for input stage coupling. That satisfied my curiosity and I haven’t messed with them since. The limited capacitance and voltage ranges didn’t help.
 
I played with some a couple of years ago, and found that their voltage rating needs to be generously derated or else they'll fail short, with ever increasing leakage that turns into a short on the supply. I was using a 25V part at 22V, something you can do easily with a traditional Al electrolytic but not an Oscon.

I gave up because it's also hard to find these caps with high voltage ratings. I bet they're great for what they were designed for - super low impedance caps for switchers that power low voltage CPU cores. For audio, they don't seem to do anything better than a conventional wet Al electrolytic, especially one of the newer high temperature low impedance models, which can have spectacularly long life and great performance.
 
Monte McGuire said:
I played with some a couple of years ago, and found that their voltage rating needs to be generously derated or else they'll fail short, with ever increasing leakage that turns into a short on the supply. I was using a 25V part at 22V, something you can do easily with a traditional Al electrolytic but not an Oscon.
That sounds something like tantalums. I was in a thread in the last year or so, forget if it was here or diyaudio, but a Kemet tantalum datasheet explained about the voltage rating, that the chance of failure started going UP as the operating voltage exceeded HALF of the stated voltage rating. This is not at all like what we've traditionally learned about aluminum electrolytics.
 
benb said:
That sounds something like tantalums. I was in a thread in the last year or so, forget if it was here or diyaudio, but a Kemet tantalum datasheet explained about the voltage rating, that the chance of failure started going UP as the operating voltage exceeded HALF of the stated voltage rating. This is not at all like what we've traditionally learned about aluminum electrolytics.
unlikely to be the same mechanism but tantalums were notorious fire starters. I expect modern tantalums are better, and likewise the modern OSCONs too, but respect voltage ratings (and ripple current ratings in PS designs).

JR
 
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