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Altera_Forum's avatar
Altera_Forum
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7 years ago

MAX 10: LVDS electrical characteristics and compatibility

I am intending to use MAX 10's true LVDS IOs for both TIA-644 and TIA-899. The True LVDS IOs mention that they can be used both for Tx and Rx. The electrical characteristics of MAX 10's LVDS differ from the standard LVDS (TIA-644) and M-LVDS (TIA-899) as detailed below:

MAX 10

TIA-644

TIA-899

Vos (V)

1.125 - 1.375

1.125 - 1.375

0.3 - 2.1

Vod (mV)

247 - 600

247 - 454

480 - 650

Can MAX 10's IOs still be used for both of these standards? If yes how? Do I need to use a differential to differential amplifier in case of TIA-899?

Secondly my understanding of the difference between True LVDS and Emulated LVDS is that former's receiver is terminated internally and thus does not need an external termination. Please correct me if I am wrong.

3 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    7 years ago

    --- Quote Start ---

    Secondly my understanding of the difference between True LVDS and Emulated LVDS is that former's receiver is terminated internally and thus does not need an external termination. Please correct me if I am wrong.

    --- Quote End ---

    Not quite right. Emulated LVDS is a TX feature. LVDS RX are true LVDS receivers on all banks where they are available. MAX10 doesn't provide on-chip parallel termination for LVDS RX. Cyclone V e.g. does. See this doc https://www.altera.com/content/altera-www/global/en_us/index/documentation/sam1394433606063.html

    MAX10 can basically implement Bus-LVDS (M-LVDS), the specifications are almost similar to TIA-899.
  • Altera_Forum's avatar
    Altera_Forum
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    7 years ago

    Thanks for clearing the termination issue.

    But how this mismatch of offset voltage is going to be catered for? MAX 10 has a Vos of 1.125 - 1.375 V whereas TIA-899 has a Vos of 0.3 - 2.1 V.
  • Altera_Forum's avatar
    Altera_Forum
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    7 years ago

    --- Quote Start ---

    But how this mismatch of offset voltage is going to be catered for? MAX 10 has a Vos of 1.125 - 1.375 V whereas TIA-899 has a Vos of 0.3 - 2.1 V.

    --- Quote End ---

    I guess you don't fully understand the meaning of the parameters. Vos is output common range, the effective requirement is that Vos extrema of all M-LVDS transmitters are within the guaranteed Vicm range of all receivers.