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SN74LVC8T245PWR-Level translator maximum operating speed calculation

Rajesh
Expert 1010 points
Other Parts Discussed in Thread: SN74LVC8T245, SN74AVC8T245

Dear All,

Good Day, I am using SN74LVC8T245PWR as a level translator from the 2.5V to 3.3V.VCCA=2.5V and VCCB=3.3V and some signals are clock signals worst case maaximum frequency is 220MHz. Let me know that whether this leveltranslator will support this speed and how to find the maximum speed of this leveltranlator from the datasheet.

Regards,

Rajesh.S

  • 0
    TI__Expert 4705 points

    Hi, Rajesh,

    For SN74LVC8T245, from 2.5v to 3.3V translation, it can not support up to 220MHz, since it is the 3.3V part, I prefer you to use the SN74AVC8T245, it can support 220MHz translation from 2.5V to 3.3V. I think you can find the Pin-pin compatible part.

    BR
    Junjie

  • 0 in reply to Junjie Mai
    Expert 1010 points

    Dear Sir,

    But in your websiite in the following location it is mentioned that these level translator SN74LVC8T245 can support  upto 500Mbps

    http://www.ti.com/product/sn74lvc8t245

    How to find the Max data transfer rate from the datasheet.

    Regards,

    Rajesh.S

  • 0 in reply to Rajesh
    TI__Expert 4705 points

    Rajesh,

    For SN74LVC8T245, the max DataRate only can be got when tranalate from 3.3V to 5V or 5V to 5V , not your application from 2.5V to 3.3V. Usually, the DataRate is related to the power supply combination, the higher , the faster, you can see in the datasheet, the higher power supply , the smaller Tphl and Tplh, which means the faster.

    So far, you only can check the propergation delay in the datasheet, and know the trend of the datarate, but can not know what the max datarate is. we plan to add this informaiton to the datasheet later. sorry for missing this information.

    Could you find the Pin to Pin compatible for SN74AVC8T245 to replace your LVC8T245? if you definitely need the 220Mhz, I prefer you to change.

    BR

    Junjie

  • 0 in reply to Junjie Mai
    Expert 1010 points

    HI,

    Thanks for the information. send me the maximum data transfer rate of this buffer for the different configurations. Whether this same buffer(SN74LVC8T245) will support 220MHz in the 3.3V to 2.5 Transformation.

    Regards,

    Rajesh

  • 0 in reply to Rajesh
    TI__Expert 4705 points

     

    Rajesh,

    So far no detail data , we need to do the test or simulation to get the detail data for each power supply combination.  and then add those informaiton to the datasheet. this SN74LVC8T245 can not support 220Mhz for  3.3V to 2.5V tranaltion. but the SN74AVC8T245 can.

    BR
    junjie

  • 0 in reply to Junjie Mai
    Expert 1010 points

    Hi,

    Thanks for the information, I will move to SN74AVC8T245 level translator for the critical signals. Any way can you send the MAX data rate of SN74LVC8T245 from 2.5v to 3.3v conversion.

    Rajesh.S

  • 0 in reply to Rajesh
    TI__Expert 4705 points

    Rajesh,

    Yes, for that data, after I get it I will let you know as soon as possible. suppose next week I will provide you that data.

    BR
    junjie

  • 0 in reply to Junjie Mai
    TI__Expert 4705 points

    Rajesh,

    Based on the data from simulation, the maximum data rate for SN74LVC8T245 can reach up to 110MHZ at 2.5 to 3.3 translation with 15pF.

    BR
    Junjie