Should I use an industrial marked FPGA with my industrial temperature rated DDR SDRAM?

Description

DDR SDRAM datasheets list SDRAM temperature ratings as follows:

• Commercial: 0^O to 70^O
• Industrial: -40^O to 85^O

However, these temperature ratings are for ambient temperature, while Altera qualifies FPGA temperature ratings for junction temperature. The difference between the ambient and the junction temperature can be ten of degrees so if you are going to use the industrial DDR SDRAM devices at 85 degree, then you should use the Altera industrial-grade FPGAs.