In a message dated 09/07/2000 3:47:57 AM US Eastern Standard Time,
[log in to unmask] writes:

>
>  With respect to SIR and Electromigration testing, can anyone please
>  enlighten me about the two Bellcore standards that are often quoted by flux
>  manufacturers. Some datasheets I see quote Bellcore TR-NWT-000078 Issue 3
>  and some Bellcore GR-78-CORE. The test conditions look quite similar. Has
>  one standard superseded the other or are they both current?

The TR-78 document was superceded in September 1997 by the GR-78 document.
The SIR test is essentially the same between the two documents.  The
electromigration test changed from 596 hours at 85C/85% RH in the TR-78 spec
to 596 hours at 65C/85% RH in the GR-78 spec, with the pass-fail criteria
remaining the same.

If the paste or flux passed TR-78 SIR, then it passed GR-78 SIR, although the
manufacturer *should* have had it tested to GR-78 and updated their data
sheets by now.

>
>  Ultimately, which is the most suitable for todays Telecomms applications?

Define suitable.  Using the classical thinking of a present standard
superceding an outdated standard, the GR-78-CORE document would be "suitable".

>
>  Looking forward to your responses.

Must be a slow day for you.........

Doug Pauls
Technical Director
CSL

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