Hi Nagaraj -
I don't know what you mean by Bed of Nails testing. People mostly talk
about bed-of nails in connection to a functional test where the nets are
accessed through a matrix of pogo-pins. ICT (in-circuit Test) is in
general not a functional test, but  is in the simplest form a test where
the impedances of all accessible nets are measured to help detect
manufacturing defects like shorts, opens, incorrect values, incorrect
polarity etc. ICT is also referred to as Node Impedance Test (NIT).
Modern ICT testers have many capabilities beyond just measuring
impedance, such as boundary -scan and programming of non-volatile
memory. Check also Agilent's testjet.

Flying probe test is the prototype or low-volume version where the
probes represent a very flexible fixture that can be programmed to hit
all the nets in turn.  ICT tester for higher volume will have a custom
fixture for each board, with pogo-pins that connect to all nets
simultaneously.

Agilent and Teradyne are major vendors of in-circuit test equipment. You
can check their websites for more information

http://www.teradyne.com/
http://www.home.agilent.com/

Med vennlig hilsen. Best Regards.
__________________________________________
Haldor Husby
Senior Development Engineer
Data Respons Norge

[log in to unmask]
www.datarespons.no



On Mon, 24 Jul 2006 21:43:54 +0100, ert ert <[log in to unmask]> wrote:

>Hi All,
>
>I have studied and followed ICT testing on layout with constraint
requirements like placing in grids, spacing b/w prope pads, component to
Probe pads spacing,..etc But I do wish to know how the ICT testting is
carried out? Is it similar to Bed of Nails test and Flying prope test?
>
>If any one has any documents or have practical experience on this can you
help be understanding this.
>
>Thanks much in advance.
>Nagaraj
>
>
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