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foft's avatar
foft
Icon for Occasional Contributor rankOccasional Contributor
5 years ago

MAX10 weak pull-ups and leakage current

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?

7 Replies

    • foft's avatar
      foft
      Icon for Occasional Contributor rankOccasional Contributor
      5 years ago

      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's avatar
        AminT_Intel
        Icon for Regular Contributor rankRegular Contributor
        5 years ago

        Hello,

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

        Thanks.