[sdiy] SMD capacitors : choosing dielectric type

[Jay Schwichtenberg]

Frédéric,

I've used PPS caps in audio DAC/ADC filters on sound cards and thought they
sounded pretty good. When we were doing tests on our circuits we found the
converters and op-amps were more critical than the caps in the circuit. I
still use one of the cards in my DAW and it still holds up to a lot of newer
cards. Biggest problem is that the cards are PCI and that's going away
pretty fast now.

We used the ECHU caps from Panasonic.

But here's the problem. If you look at the data sheet the flow/reflow
soldering temperature it is 260C for these parts. If I've done my math right
that is 500F. Now the Kester 331 organic/water soluble and 245 no clean
solders have a soldering temp of 600F-700F. So you have to be really fast
soldering these things down. There is also no reuse if you pull one off a
board. There is a real high probablity it will be melted.

Jay S.


-----Original Message-----
From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Frédéric Meslin
(Gmail)
Sent: Monday, February 06, 2012 1:57 PM
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] SMD capacitors : choosing dielectric type

Hi Jay S.

Thank you for your answer but soldering issues with 1206 or 805 SMD
caps are not big problems for me. I have the tools for soldering
this kind of components.

I think PPS caps are rather good according to this article :
http://www2.electronicproducts.com/PPS_stands_in_for_polycarbonate_in_film_c
apacitors-article-NOVDEA1-nov2000-html.aspx

Do you think so ?

Thank you by advance,
Frédéric.


> I don't know which caps you are looking at or how you plan on soldering
> them.
>
> But one issue with plastic SMD caps is they can be very temperature
> sensitive. There are some that you can melt quite easily soldering with
> a soldering iron. So check your specs about soldering them before you
> buy.
>
> Good luck!
> Jay S.

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