Sounds like you are alternately immersing the part in liquid nitrogen, then
applying a blowtorch.

As long as your rates of thermal expansion/contraction coefficients are not
greatly different, you should not see any cracked, intermittent or open
solder joints due to stress.  Check with Xilinx if its not in their
datasheet.  Your board vendor should have data available on the materials
being used.

Michael Howell, Electrical Engineer
Lighthouse Worldwide Solutions
1221 Disk Drive
Medford OR 97501
Tel 541-770-5905 x 130
Fax 541-770-2033


-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of
Mariani, Stephen
Sent: Monday, January 23, 2006 4:53 AM
To: [log in to unmask]
Subject: [DC] Component rate of change ramping temperature


We need to know how component vendors document the rate of change for
ramping temperature up or down.

A simple example of interest is going from storage to operational
temperature range, say from the low storage temp to the low operational
temp. For example Xilinx Virtex2 Pro going from -65C to -40C. Or PowerPC
going from -55C to -???C (see below).

Similar for going from high temp storage to high temp operating.

How fast is too fast? 20C per minute? 10C per minute? 5C per minute?

Thanks


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