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SN65LVELT23 Differential LVPECL/LVDS Buffer

Vladimir Portnov
Prodigy 90 points

Other Parts Discussed in Thread: SN65LVELT23

Hi ,

The SN65LVELT23 Diff. to LVTTL buffer is titled as "LVPECL/LVDS Buffer " .

For any reason it's datasheet contains only  LVPECL input characteristics at VCC = 3.3V .

What about LVDS input support by this decvice ? What should be the input level requirements in this case of LVDS operation ?

Thanks

Vladimir

  • 0
    TI__Mastermind 20820 points

    Hi Vladimir,

    The inputs of the SN65LVELT23 are defined as LVPECL inputs therefore the LVPECL DC characteristics are only specified in the data sheet.

    The VICM range and the VPP (differential input voltage form the AC Characteristics table) of the device though show that we do support the LVDS levels of 1.2V common mode and 400mV differential voltage.

    Regards,

    Mike

  • 0 in reply to Michael Peffers
    Prodigy 90 points

    Hi Mike ,

    Thanks a lot for your answer .

    Unfortunately It is still not fully clear to me.

    The standard LVDS CM output level is 1.25V , so according to VIHCMR  min = 1.2 V value this device is OK with LVDS signal input . 

    But value VIL min = 1490mV is absolutely contradicts with the VIHCMR  min = 1.2V value from the same table in datasheet and states this device as doesn't support LVDS .

    Please advice .

    Vladimir

  • 0 in reply to Vladimir Portnov
    TI__Mastermind 20820 points

    Hi Vladimir,

    I understand your confusion, the data sheet was not assembled in clear way. The SN65LVELT23 device is compatible with LVDS voltage levels though and it should have been clearly identified in the data sheet. The VIH and VIL levels that are listed in the data sheet are obviously levels that support the LVPECL standard and should not be confused with the LVDS standard.

    It can be seen though by the VICMR of 1.2V min and the differential voltage swing of 200mV min that LVDS levels can be supported by this part. Please visit: http://www.ti.com/tool/sn65lvelt23evm and request an EVM so that you can do an in house verification of the part!

    Regards,

    Mike

  • 0 in reply to Michael Peffers
    Intellectual 450 points

    Hi there, any chance that the datasheet will be updated with clear LVDS input specification soon?  This answer is from 2013 and datasheet still from 2009.

    thanks

    David