It seems only a few values are readily available in networks and arrays;
you have to do your homework in advance and make sure stock is available
someplace. Stock for these parts is hard to come by in domestic U.S
market.
We are using networks and arrays on medium/high volume products, and where
we use many of a few values on low volume products.
Ex: One product, estimated yearly build of 500, uses 38 cap arrays and 57
resistor ntwks, and we try to use these same values on other products. We
use un-imaginative values, too, in order to get parts (such as 1K, 10K,
100K, 0.1uF, 0.001uF) and find as many good vendors as possible.
Stock is getting better as time goes by.
My 2 cents worth.
Roger M. Stoops, C.I.D., PCB Designer
Trimble
Engineering and Construction Division
Susana Anaya
<sanaya@QUALC To: [log in to unmask]
OMM.COM> cc:
Sent by: Subject: Re: [TN] Capacitor 0603 vs 0402...why not networks and
TechNet arrays?
<[log in to unmask]
ORG>
08/09/01
03:31 PM
Please
respond to
"TechNet
E-Mail
Forum.";
Please
respond to
Susana Anaya
Hi, the lurker comes out of the shadows here to ask all you wise ones
what's up with availablity for lower volumes. I ask because the reps that
have been suggesting them to me and haven't said a word about this (and I
am one of those not looking for thousands monthly)....sanaya.
At 08:45 AM 8/9/01 -0700, Greg Scott wrote:
Steve,
Our materials and component Engineers encourage us NOT to use chip
resistor networks
but we do use alot of capacitor arrays. The reason Is availability
unless you buy by the thousands monthly.
Greg Scott
Cray Inc.
"Stephen R. Gregory" wrote:
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-
Hi all,
I'm brainstorming on risks and benefits of 0603 caps
vs 0402 caps.
If the cap value, voltage rating, dielectric material,
terminations, and
use conditions are the same, would one be better than the
other? My
thoughts are it would be a wash or at least not significant.
Here's what I
have so far:
Benefits of 0402 vs 0603:
Smaller size reduces thermal stress/strain on solder joints
from CTE or
board flexing.
Smaller size uses less real estate on board
Risks of 0402 vs 0603:
Equipment may have difficulty placing
Thinner dielectric spacing to achieve same capacitance, cap
higher failure
rate
Smaller size, cracks easier to develop
Higher risk of tombstoning
What do you all think? I'm sure I missed something,
maybe even
wrong on some of the above.
Thanks,
Glenn
---------------------------------------------------------------------------------
Technet Mail List provided as a free service by IPC using LISTSERV 1.8d
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt delivery of Technet send the following message: SET Technet NOMAIL
Search previous postings at: www.ipc.org > On-Line Resources & Databases > E-mail Archives
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
---------------------------------------------------------------------------------
|
