Hi K.K.

     Well, a couple of things.

     1. The HP3070 has the typical frequency range choices of 128, 1024 and
     8192HZ. I'd love to have a 100KHZ range.  If your system does, please
     let me know so I can find out why HP is holding out on me.  <LOL>

     2.  Your ICT people are correct in stating that a Kelvin measurement
     would be recommended for any low value component.  This typically
     applies to resistors < 10 Ohms, caps < 100 pF, etc.   Two closely
     spaced test points right next to the low value component would be
     really keen.

     3.  The thing your ICT people haven't mentioned is that the HP3070,
     lacking two test points, will assign two wires (resources) to the one
     test probe.  While this is not an "ideal" Kelvin measurement, it's
     pretty darn close.

     Realistically, I have never been able to force my CAD people into
     giving me two test points on any node. Space is such an issue, that
     I'm extremely lucky to get one, and I'm fighting for pad size and
     point-to-point spacing on that.

     Answer: wack away at your Test Engineers with a broom until they can
     provide you BOTH ends of the spectrum: the wishlist and the "must
     have's"

     Good wackin' ahead!

     Robert D. Green
     Manager, Test and CAM Engineering
     HADCO Corp.


______________________________ Reply Separator _________________________________
Subject: [TN] ICT Test Pads on PWB
Author:  KK Chin <[log in to unmask]> at smtplink-hadco
Date:    6/29/99 10:24 AM


Hi Technetters,

I'm a layman in In-circuit test. The ICT people told me that low impedance
passive devices (say, <10 ohm) require kevin connection for the test, so 2 test
points are needed at the circuit nodes on each side of the device. It's okay to
me for resistors, but how about the capacitors and inductors?
Knowing that the typical HP3070 tester has the test frequency of 1KHz, 10KHz and
100KHz, my calculation is that <10 ohm implies <16uH at 100KHz for inductors and
>160uF at 1KHz for capacitors. If this is the case, I'm afraid most capacitors
and inductors in my product requires 200% nodal access.
My questions are:
- Is this requirement documented somewhere?
- Is it really applicable to inductors and capacitors?

Thanks!
K.K. Chin
Artesyn Technologies,
Fremont,CA