well, agree with you on the UFO test.  However, the stuff I saw
(resistor network) was double sided ceramic with flip chip like ball
connect.  The component side was encapsulated with epoxy, just like your
IC CSP...very impressive and fully testable...Don't know how they pick
and place...with the round encap top. (I am sure you can't buy
them....got be a special part...fit the board perfectly...)..I think the
ESD, EMI, RFI should be the same as a plastic IC moudule...Boy, I just
love the smart design...
 
jk

-----Original Message-----
From: Mark Ross [mailto:[log in to unmask]]
Sent: August 9, 2001 10:22 PM
To: [log in to unmask]
Subject: Re: [TN] Capacitor 0603 vs 0402...why not networks and arrays?


My experience is that it depends.  For one thing a 25KV ESD discharge
happily jumps over an 0402 but not a 1206 and sometimes not an 0805.  As
nice as small parts are they don't always fit the bill, especially for
ESD,EMI,RFI etc.
 
Another thing I have seen happen is when a product gets bombarded with
an external radiation source, the smaller caps don't even look like a
cap electrically.
 
The test I am talking about is a 0-10 GHz sweep at 1v/1M.  This is what
I like to call the UFO test, because when tested on vehicle
applications, the lights on the dash glow without vehicle power, but
you'll be in trouble if your electronics fail.  
 
Also on power applications for UL requirements a 1206 might fit the bill
for trace and or pad spacing at 120Volts, but a 0603 certainly will not.
 
Also on applications where board layers are restricted i.e. double or
even worse single layer boards, on a 1206 you can jam between 3 and five
traces under a 1206 where a 0402 you won't get 1 or maybe 1 if you're
lucky.
 
I still laugh at those who said through hole technology is dead years
ago.  Hmmm seems to still be real active to me.  Not to mention all that
darn machinery for making through hole parts was paid for long ago.  Of
course when it breaks down, you might have to dig up the guy (literally)
that knew how it was designed and how to fix it, but hey, with that
cloning thing maybe.....oh never mind.
 
Mark Ross
 

----- Original Message ----- 
From: Pelkey, Glenn <mailto:[log in to unmask]>  
To: [log in to unmask] <mailto:[log in to unmask]>  
Sent: Thursday, August 09, 2001 11:41 AM
Subject: Re: [TN] Capacitor 0603 vs 0402...why not networks and arrays?

Hi Steve and everyone,
 
    Thanks for the inputs.  You guessed it...real estate is at a
premium.  Individual caps are used here for electrical performance and
placing them at specific locations is critical.  Still, arrays arrays
are something to keep in mind in the right application.
 
Thanks again,
 
Glenn

-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Wednesday, August 08, 2001 5:46 PM
To: [log in to unmask]; [log in to unmask]
Subject: Re: [TN] Capacitor 0603 vs 0402...why not networks and arrays?


Hi Glenn! 

I've read the responses you've received to your question (they've all
been 
good), and want to ask another question... 

I assume the reason to use smaller passive components, is to reduce the
real 
estate needed by these components. My question is; why isn't there more
use 
of chip resistor networks and capacitor arrays? 

To me, it seems obvious that the use of these components will reduce
real 
estate, but I don't see them being used as often as they could
be...maybe I'm 
not aware of the electrical characteristics or something else, but I
wonder 
why they aren't used more often in designs that are tight for space than
what 
I've seen so far... 

Can anybody shed some light on this? 

-Steve Gregory-