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avilo
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Registered: ‎09-27-2019

Replacement for XC7K355T-1FF901I

I have an old PCB design that uses the XC7K355T-1FF901I and it seems to have gone obsolete. Is there a pin-for-pin compatible part that I can replace it with? It needs to have (mostly) all the same specs and needs to have the same footprint.

Thank you very much

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drjohnsmith
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Registered: ‎07-09-2009

why do you say obsolite

 

Pile of them here at the autherised distributer

 

https://www.digikey.co.uk/products/en?keywords=XC7K355T

 

 

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avilo
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Registered: ‎09-27-2019

Unfortunately, there is only 1 in stock in that entire list. I only say obsolete because it's out of stock everywhere and no one seems to be re-stocking it anytime soon.

Another thing I am curious about is, if you open the datasheet and look at the part number descriptions, it seems like this one is missing a character. It needs a V or a G after the FF package type. I've attached the picture from the datasheet.

Thanks for helping!

Xilinx FPGA.PNG
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drjohnsmith
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Registered: ‎07-09-2009

did not realise. Last I looked it was on 10 to 12 week delivery
interesting,

re the number XC7K355T-1FF901I your asking about

where have you gotten that from

Im an engineer, and we are terrible at telling purchasing departments the full part number,

The V / G is meaning lead free
so if your part number has no V or G, you dont need lead free.

That could be because your engineers "forgot" this, or it could be that your process does not need lead free, or that you could use lead free or with lead int he mix.

But that does not answer your initial question, where have all the XC7K355T gone.


A wider search shows lots form "alternate" suppliers

https://www.digipart.com/part/XC7K355T-1FFG901C

I wonder whats happening,
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u4223374
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Registered: ‎04-26-2015

As @drjohnsmith  has said, it looks like the part number you've specified is one of the rare parts that uses leaded solder. You might want to verify that; while leaded solder is certainly used in some places (I know that the military is rather fond of it) almost any commercial product these days would be lead-free.

 

If you do need a leaded part, then get in touch with Digikey (or any other distributor). They'll be happy to order some for you, it'll just take a few months. You need to plan your supply chain to take this into account.

avilo
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Registered: ‎09-27-2019

Thanks again, John. I appreciate your time. Ultimately however, none of those suppliers are on my approved list where I can buy from. Also, 10-12 weeks is quite some time for a lead time. The fact that they are non-stocked leaves me to believe that they are an older part, on their way to obsolescence.

At the end of the day, this design is very old, and while I can possibly wait the 12 weeks, do you (or anyone) know of a newer part that has taken this one's place?

Thanks again!

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drjohnsmith
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Registered: ‎07-09-2009

Unlikely to be on way to obselecance.

its just that very few people need parts with lead in them,
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Registered: ‎01-22-2015

@avilo 

...do you (or anyone) know of a newer part that has taken this one's place?

UG475 and AR43204 describe pin-compatibility between 7-Series devices.

https://www.xilinx.com/support/answers/43204.html

According to AR43204, “Kintex-7 devices are pin compatible with other Kintex-7 devices in the same package.”

So, according to Table 3-3 in UG475, the XC7K355T, XC7K420T, and XC7K480T are pin-compatible in the FF901 package.

However, “pin-compatible” can have some caveats and exceptions.  So, you should carefully compare the package-files for the two pin-compatible devices.

https://www.xilinx.com/support/package-pinout-files/kintex-7-pkgs.html

Mark

 

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avilo
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Registered: ‎09-27-2019

Thank you very much, Mark! I will look at these links. Much appreciated.

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drjohnsmith
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Registered: ‎07-09-2009

One thing,
even compatible parts,
need the code to be re compiled
so you could end up with multiple versions of the code.
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