PEN, PPS caps?

[Ian Fritz]

Hi group --

Has anyone worked with PEN (polyethylene naphthalate) or PPS
(polyphenylene sulphide) caps.  I read about these on the Siemens
website (www.siemens.de). The PPS has only a -100 ppm/K tempco. For some
reason, they only shows rather largish values (>20 nF).

I also have discovered that Mallory still is listing polystyrene, as
well as porcelain and glass-encapsulated porcelain (which I hadn't heard
of before).

Also it looks like Cornell-Dubilier is still making mica caps, and over
a fair range of values.

  Ian