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Altera_Forum's avatar
Altera_Forum
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15 years ago

1.8 V Lvcmos

Hi @ all,

I want to use LPDDR RAM which makes 1,8 V LVCMOS outputs necessary.

In the Pin Assignment Window, I can only choose 1.8 V (without the additional specification LVCMOS). Is this option equal to the 1.8 V LVCMOS standard?

Does anybody know something about this problem?

Regards

Spitzinger

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    --- Quote Start ---

    Is this option equal to the 1.8 V LVCMOS standard?

    --- Quote End ---

    Yes, surely.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    You can check the exact characteristics for a given I/O standard in the data sheet for the FPGA in question.

    I just looked at a Cyclone IV data sheet, and it actually groups together 1.8V LVTTL and LVCMOS into one item with the same specs. The same is true for 2.5V. For 3.3V or 3.0V, there are different specs listed for LVTTL and LVCMOS.
  • Altera_Forum's avatar
    Altera_Forum
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    15 years ago

    Also switching between 3.3V LVTTL and CMOS doesn't actually change the logic levels. It only changes the calculation of current strength.