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SN74TVC3010: Bidirectional Translation Using a TVC Device

Satoshi Okamoto
Intellectual 430 points
Part Number: SN74TVC3010
Other Parts Discussed in Thread: LSF0108

Hi There,

We are considering the adoption of "SN74TVC3010".
I want to check how to use it.

[conditions]
・Each FPGA operates voltage at 1.8V.
・FPGA (A) and either FPGA (B) / FPGA (C) communicate.
・The communication speed is 33MHz.
・Communicate in both directions.

【Check】
1.Is it possible to level translation of 33MHz ?
2.Is a circuit configuration that connects in parallel acceptable ?
3.Is data communication (33MHz) possible with the configuration of the attached document?

Best regards
- satoshi

Bidirectional Translation Using a TVC Device.pdf

  • 0
    TI__Mastermind 43696 points

    Hi Satoshi,

    1. The part is rated up to 100MHz - so 33MHz should be okay.

    2. That should be no issue - this will add more capacitance to the line - but the part should be able to handle parallel configurations.

    3. That 10kohm pull up is too large (this is the RDpass resistor as denoted in the datasheet). I would look to shrink this by at least a factor of 10.

    One more thing to note if using this part in this type of application is that if you want to translate from 3.3V to 1.8V - the amount of current at the 1.8V side will degrade the voltage if it is larger than a ~1mA - this is something to be aware of when designing this.

    One question however - after looking at the block diagram - if you can share - why are you looking to use level translators in this application? All FPGA's are communicating at 1.8V, and while this part can help with the level translating application - I am not sure if it is necessary. 

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Intellectual 430 points

    Hi Parker,

    Thank you for your answer.

    Level translation is required because the current model supports 3.3V.
    The new model operates at 1.8V.

    New model:BOARD(A),(B),(C)
    Current model:BOARD(D)

    Another device candidate is "LSF0108".
    The internal structure looks similar.

    Can the same communication be performed with "LSF0108"?

    Best regards
    - satoshiBidirectional Translation Using a TVC Device‗add.pdf

  • 0 in reply to Satoshi Okamoto
    TI__Intellectual 2694 points

    HI Satoshi-san,

    How many channels/bits do you need for the communication from FPGA A to B/C/D? We can recommend best options based on this information.

    Thank you,


    Regards,

    Sandesh

  • 0 in reply to Sandesh Rawool
    Intellectual 430 points

    Hi Parker,

    Thank you for your answer.

    The data communication bit is 83 bits.
    The challenge is that bidirectional communication (33MHz) works in parallel.

    Best regards
    - satoshi

  • 0 in reply to Satoshi Okamoto
    TI__Intellectual 2694 points

    Hi Satoshi-san,

    Just to clarify the question, SN74TVC3010 device has 10x 1:1 switches or channels (+1 used as reference for translation) and the LSF0108 has 8x 1:1 channels. 

    Wanted to make sure we have optimal solution for you based on how many pins are connected from FPGA A to B/C/D. This will will to identify the best device configuration.

    Thank you,


    Regards,
    Sandesh

  • 0 in reply to Sandesh Rawool
    Intellectual 430 points

    Hi Sandesh,

    Thank you for your answer.
    Sorry it's taken me so long to get back to you.

    We proceeded with the examination with LSF0108.
    Because, SN74TVC3010 could forget the external power supply.

    We evaluated LSF0108.
    There was almost no delay if there was enough driven LOW.

    Therefore, we adopted LSF0108.
    We thank you for your cooperation.

    Best regards
    - satoshi