Re: MAX10 weak pull-ups and leakage current

foft · ‎02-08-2021

I'm seeing significant impact from enabling weak pull-ups on pins other than the one I am using.

The specific case is as follows:

Device 10M02SCU169C8G.

In this design I have C1 and D1 connected together. I saw them pulling up with approximately 160uA when tri-stated. I.e. I see 0.8v on the pin if I use a 5K resistor to pull to ground.

I noticed that if I disable the weak-pull up on C2 then the leakage current on C1/D1 vanishes. Note that in my design C2 is actually an unused pin, the weak pull-up was on by default by the 'as input tri-stated with weak pull-up' option for unused pins.

Is this a known issue, perhaps related to the other half of a differential pair?

AminT_Intel · ‎02-10-2021

Hello,

This may happen because of leakage current in Max 10 device. There is a detail about tristated I/O pin on page 9 from this link: https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/max-10/m10_datasheet.pdf

Thanks.

foft · ‎02-11-2021

I saw that, but its talking about +/-10uA. 160uA is a fair bit higher. It does say that the 10uA may be exceeded when using the clamp diodes. In fact that isn't what I see here. I see it happen not with the clamp diodes but the weak pull up on another pin that I'm not using.

AminT_Intel · ‎02-15-2021

Hello,

May I know which version of Quartus are you using and if you can share you sample design.

Thanks.

foft · ‎02-19-2021

I've seen this in Quartus lite versions for the last few years, now using v20.1. I'll post the .qar this evening.

AminT_Intel · ‎03-07-2021

Hello,

Is there any update from your end? I will close this case in 3 days from today if there is no update from you.

Thank you.

AminT_Intel · ‎03-14-2021

We do not receive any response from you to the previous question/reply/answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.

foft · ‎03-15-2021

Sorry I was a bit caught up with some things, I'd post it now but guess its too late.