CPLD speed/temperature equivalent

I have a ALTERA MAX3000A CPLD with two inscriptions:

EPM3256AFC256-7 --> commercial temp, speed grade 7
and
EPM3256AFI256-10 --> industrial temp, speed grade 10

I bought the industrial one.
Are this two CPLDs equivalent???
If yes -> if I buy the commercial, speed grade 7 - is this CPLD equivalent 
to the industrial temp, speed grade 10???

Thanks for your answers in advance, Manfred 

Manfred Balik wrote:
> I have a ALTERA MAX3000A CPLD with two inscriptions:
>
> EPM3256AFC256-7 --> commercial temp, speed grade 7
> and
> EPM3256AFI256-10 --> industrial temp, speed grade 10
>
> I bought the industrial one.
> Are this two CPLDs equivalent???
> If yes -> if I buy the commercial, speed grade 7 - is this CPLD equivalent
> to the industrial temp, speed grade 10???
>
> Thanks for your answers in advance, Manfred

Double marking is a standard practice for many
chip manufacturers including Lattice.  If the part
is marked for commercial and industrial with
different speed grades, it means the part has
been characterized and presumably tested to
meet those speed grades at the associated
range of temperatures specified for commercial
or industrial parts.

Generally this double marking is noted in the
data sheets and you can "cross-order" the
equivalent part using the other number.  The
price is generally the same, too.  If there is
no such policy noted in the data sheet, I
would suggest ordering the part using the
number you need, since there is no guarantee
that another batch of parts will be dual-marked
and more importantly dual-characterized and
tested.

Regards,
Gabor