Reverse aspect ratio capacitors

(I didn't get any response to this over on sci.electronics.components so I'm trying it here...)

Could someone who's used 0508 and/or 0306 sized capacitors comment on whether or not you had any particular difficulties in manufacturing relative to the use of 0805s and 0603s? Our contact at our current contract manufacturer initially said he'd never _heard_ of 0306's and, after talking to some of his guys, said that, yes, they had used them, but sometimes ended up having to laser trim the footprints (presumably so as to avoid solder bridging between the pads or part misalignment or somesuch). I'm curious as to whether this is a real problem with reverseaspect ratio parts, or if it's a lot of FUD on their part... I'm really surprised that there's been so much resistance to using the things!

Thanks,

---Joel Kolstad

Reply to
Joel Kolstad
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I used 0306 parts a year or two ago and I had no problem at all with them. My board manufacturer was somewhat higher end (Tyco Santa Clara, I seem to recall), but with the proliferation of smaller parts (0201 come to mind) no PCB manufacturer that does fine pitch should really have any issues with them.

Note that the stuff/reflow people need to take care with the solder stencil, but there's plenty of knowledge out there to deal with this stuff.

Cheers

PeteS

Reply to
PeteS

What advantage do these components offer over the incumbent types?

I'm sure there are some, just not thinking of them, only the disadvantages, such as not being able to route as many traces through the middle.

Reply to
cs_posting

These components have lower ESL (because they are physically shorter in the signal path).

Cheers

PeteS

Reply to
PeteS

Roughly one quarter the equivalent series inductance, which results in a self-resonant frequency that's roughly doubled. Additionally, they more closely match the width of a 50 ohm microstrip trace (on a regularly spaced four layer .0625" board, this is usually in the ballpark of 25 mils wide), so there's a small but measuable improvement in transmission flatness.

---Joel

Reply to
Joel Kolstad

Lower inductance

Bye. Jasen

Reply to
Jasen Betts

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