Author Topic: Unused transceiver TX channels in Arria 10 device may degrade over time  (Read 3363 times)

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Offline hamster_nzTopic starter

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Via @whitequark on Twitter...

Quote
Why do unused transceiver TX channels in my Arria 10 device degrade over time?

Description

Unused transceiver TX channels in your Arria 10 device may degrade over time when using the Quartus® Prime software version 16.0 and earlier.

Full KB article at https://www.altera.com/support/support-resources/knowledge-base/solutions/rd06092016_720.html

Will be of most interest to development board users, who might not use the transceivers for long periods of time, and then need to use them.

No clear indications as to what or why...
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Offline BrianHG

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What the hell?  Quartus with Arria 10 support requires a subscription.  Once you stop paying, you cannot upgrade Quartus.  So, if I was happy with Quartus 15, stopped paying Altera that yearly fee, now all my Arria 10 devices will keep on degrading, new designs or old, unless I fork over Altera another 4k$ US so I may compile in the latest Quartus prime.

Then again, 1 Arria 10 FPGA goes anywhere from 300$ to 5K$.  But still, if I am no longer making PCBs, and I want to preserve my existing Arria 10s, I must pay Altera 4k$.

 

Offline EEVblog

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I haven't checked the datasheet, but these things usually run into the 10's GS/s, bleeding edge stuff totally reliant upon the bleeding edge process technology. Probably the geometries are so small now that there is some form of surface migration/contamination/ *insert other issue* that degrades the performance characteristics.
At least they are readily admitting it and even building it into the software warnings. In which case it must be almost a guaranteed and predictable level of degradation.
 

Offline BrianHG

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I haven't checked the datasheet, but these things usually run into the 10's GS/s, bleeding edge stuff totally reliant upon the bleeding edge process technology. Probably the geometries are so small now that there is some form of surface migration/contamination/ *insert other issue* that degrades the performance characteristics.
At least they are readily admitting it and even building it into the software warnings. In which case it must be almost a guaranteed and predictable level of degradation.
This is what Altera says in the quote:
Quote
Workaround/Fix

To preserve the performance of unused transmitter and receiver channels in Arria 10 devices you should recompile your design in Quartus Prime software version 16.0.1 or later.

That deterioration most likely has been found to happen when they leave the un-used transceivers in a specific IO voltage mode, or dedicated macrocell configuration for the pins in question when the IO is not used or defined.  Perhaps there is a bug in the silicon when leaving the cells in their default unused state which draws current on the mosfets at the pin or internal LVDs transceivers.

Again, as altera says, recompile your design in Quartus Prime software version 16.0.1 or later and the problem ceases.  Most likely, they configure the IO never to be in that discovered bugged long term deteriorating state.
« Last Edit: March 23, 2018, 12:46:38 pm by BrianHG »
 

Offline Scrts

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It sounds like if someone would sue them, then Quartus v16.0.1 subscription would become free or they'd have to come up with a tool to fix the issue :)
 

Offline hamster_nzTopic starter

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Only thing I can find on the web is that it is due to BTI (Bias Temperature Instability).

Quote
BTI is typically observed as a VTH shift after a bias voltage has been applied to a MOS gate at elevated temperature.  For example, when measured over a lifetime
of 5 years and under normal operating conditions, VTH shifts of up to 30 mV can be expected for transistors processed in a sub-45 nm technology

Here is an interesting chapter on CMOS reliablity:

http://www.springer.com/cda/content/document/cda_downloaddocument/9781461461623-c2.pdf?SGWID=0-0-45-1376227-p174706113

Neat things like "Purple plague", and pictures of electromigration damage.
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Offline amyk

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I find it more than a little coincidental that Altera is now owned by Intel, who has experienced at least two similar problems...

It should be reasonably easy to figure out the difference, just compile with the older version, then 16.0.1, and compare...
 
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Offline chickenHeadKnob

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From an article in EEtimes:
   "One reason why Altera is attractive to Intel is that Altera is already using Intel's fab to create its latest generation FPGAs and SoCs; Arria 10 FPGAs and SoCs
    are being    implemented using TSMC's 20nm process, while Stratix 10 FPGAs and SoCs are leveraging Intel’s 14 nm Tri-Gate process (see Altera & Intel to
    Collaborate on Multi-Die 14nm FPGAs). Furthermore, Altera is also using Intel's state-of-the-art packaging technologies."

So Arria come from TSMC fabs, things that make you say Hmm!

Article:https://www.eetimes.com/document.asp?doc_id=1326736
 

Offline daveshah

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I would be interested to see if this could affect any commercial products. It sounds like it only manifests itself if transceivers were previously not used at all in the bitstream and then used. The only case where that sounds like an issue is where a firmware update enables transceivers that weren't previously used, or devices which load a different bitstream for different configurations.

It sounds like it doesn't manifest itself if transceivers are in the bitstream but soft disabled, which would be a much bigger problem e.g. if you start using a previously unused SFP/SDI/whatever port.
 

Online iMo

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It could be the Aria is using flash cells for keeping the config bits of the TX channels, which may forget the setting much faster than expected (ie while running the chip at higher temperatures). Therefore you have to refresh the cells with a new bitstream from time to time :)
 

Offline NorthGuy

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Re: Unused transceiver TX channels in Arria 10 device may degrade over time
« Reply #10 on: March 24, 2018, 03:54:14 pm »
What the hell?  Quartus with Arria 10 support requires a subscription.  Once you stop paying, you cannot upgrade Quartus.  So, if I was happy with Quartus 15, stopped paying Altera that yearly fee, now all my Arria 10 devices will keep on degrading, new designs or old, unless I fork over Altera another 4k$ US so I may compile in the latest Quartus prime.

You can instantiate transceivers in your old designs and configure them as needed. This is free. You only need to wait until the information comes up on what settings are needed to avoid aging.
 

Offline Beamin

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Re: Unused transceiver TX channels in Arria 10 device may degrade over time
« Reply #11 on: March 24, 2018, 11:12:49 pm »
So the silicon in the chip wears out?  :-//
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