Static timing report done for -40° C. How useful is that in practice?

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ChRe_4711096
Level 4
Level 4
50 replies posted 25 replies posted 25 sign-ins

PSoC Creator gives me static timing reports for -40° C, and I can't find a place to change that.

When, for example, the clock summary states 72 MHz required and the maximum is 85 MHz, will my device work at 60° C or 80° C as well?

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ChRe,

Normally at lower temperatures, silicon switching is slower.   Therefore at -40C the actual maximum frequency would favor the lower limit.

As I pointed out in the earlier post, the PSoC5 has the ability to change the operating temp for the static timing analysis.   However, there is no similar way to change it for the PSoC6.

Len

Len
"Engineering is an Art. The Art of Compromise."

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Len_CONSULTRON
Level 9
Level 9
Beta tester 500 solutions authored 1000 replies posted

ChRe,

Static timing report done for -40° C. How useful is that in practice? 


Many PSoC6s are automotive-rated.  In automotive, the operational temp ranges are -40C to 125C for parts placed in the engine compartment and -40C to 85C everywhere else on the vehicle.

Although -40C is not a commonly seen temperature, it does occur.

PSoC Creator gives me static timing reports for -40° C, and I can't find a place to change that.

 

On the PSoC5, there is a place to change the operating temp parameters in the DWR/System.  Using the PSoC6, there does not appear to have this ability.

Len

Len
"Engineering is an Art. The Art of Compromise."
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Oh I absolutely agree that it makes sense to have parts that run reliably within those temperature ranges. However, that's not the point of my question.

My understanding of logic timing is very limited and everything I "know" is that timing details vary with temperature.

Is -40°C a worst case scenario with regard to timing? Then the timing report is useful for higher operating temperatures as well.

Or are higher temperatures worse? Then the timing report seems less valuable to me.

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ChRe,

Normally at lower temperatures, silicon switching is slower.   Therefore at -40C the actual maximum frequency would favor the lower limit.

As I pointed out in the earlier post, the PSoC5 has the ability to change the operating temp for the static timing analysis.   However, there is no similar way to change it for the PSoC6.

Len

Len
"Engineering is an Art. The Art of Compromise."
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odissey1
Level 9
Level 9
First comment on KBA 1000 replies posted 750 replies posted

ChRe,

I believe that timing gets worse with lowering the temperature, not rising. Somewhere I have read that this is due to the semiconductor carrier slowing down thus increased resistance and timing (but I would'n bet on this).

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