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DS90C187: Low to High / High to Low transition time specification

Kawai
Guru 19775 points
Part Number: DS90C187

Hi Team,

Regarding the following electrical characteristic, I believe LLHT/LHLT is tested for VODSEL = VIH.

Our customer receiver has tighter spec that it requires 0.4ns (max) for these parameter.

Do you have LLHT/LHLT data for VODSEL = VIL ?

If you don't have the data, could you please give us the estimation from the design point of view or simulation data ?

Best Regards,

Kawai

  • 0
    TI__Expert 4555 points
    Hi Kawai,

    Unfortunately since this is a very old part acquired from National, it will take us time to see if we have and additional data for this parameter. Thank you for your patience.

    Regards,
    Jonny
  • 0 in reply to Jonathan Nguyen
    Guru 19775 points
    Hi Jonny-san,

    Thanks for your support.

    Our customer is judging which device to use by this week. Could you please give us the information by 7/19 US time ?

    If you don't have data, we would like to have comment from design point of view.

    Generally, if amplitude decreases tr/tf time should also decrease.

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    Guru 19775 points
    Hi Jonny-san,

    Did you have chance to look into this ?
    We need your help.

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Expert 4555 points
    Kawai-san,

    Sorry for the delay in responses, but I was unable to find any resources that could help clarify that datasheet parameter. Unfortunately because this is such an old part part, we don't support any design simulations for this device anymore. We do have a newer version of this part: the DS90C189. The person in office who characterized the DS90C189 has been out of office, so I can see if he has any familiarity with how the DS90C187 was characterized when he returns.

    Apologies again for the late response.

    Regards,
    Jonny
  • 0 in reply to Jonathan Nguyen
    Guru 19775 points
    Hi Jonny-san,

    Thanks for your continuous support.

    Generally if the rise/fall slope is the same, smaller the amplitude is shorter the rise/fall time should be.

    Customer is willing to use DS90C187.

    It may be tough, however, do you know if the slope would change if the amplitude setting is different, VODSEL = H or L ?

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Expert 4555 points
    Kawai-san,

    When VODSEL = L, the amplitude will be halved, however the slope will still stay the same. So using the same 20%-80% slope margin, the typ. spec for the LVDS rise/fall time should be about 0.09 ns.

    Regards,
    Jonny
  • 0 in reply to Jonathan Nguyen
    Guru 19775 points
    Hi Jonny-san,

    Thank you so much for your support.

    Best Regards,
    Kawai