Re: [SI-LIST] : Types of Bypass Caps

Fred Townsend (
Thu, 26 Feb 1998 13:11:52 -0800

Pavlak, John M wrote:
> Since I am new to the world of High-Speed Digital design and to Mil-spec
> design engineering, maybe someone could give me some guidance. What
> type of caps would you recommend as bypass caps that will work across
> the full Military temp range of -55C to +125C? {i.e., NPO, X7R, etc}

Military capacitors are increasingly difficult to find particularly if
you need recent date codes with oxide free, shiney leads. xr7 are
equivalent to CKR05xxx or 07. Tantalum to Mxxxxx. NPO is a problem.
There is Mil series but it is so rare I have forgotten what it is
called. For most applications of that kind I use CMR04, 05, 07 (silver
mica). However the CAD people don't like them because the lead spacings
are on fractional centers rather than decimal. For really demanding use
I go to a commercial glass such as a Vitramon. You will probably need
to go to commercial "Computer Grade" aluminum electrolytics too.

Fred Townsend
DC to Light Consulting Services
Silicon Valley