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Original question:

LSF0108 Switching Characteristics - Maximum Propagation Delay?

LSF0108: Switching Characteristics

Nanjunda M
Expert 2485 points
Part Number: LSF0108

Hi,

I'm looking for the particular timing parameters for LSF0108:

tpd (Propagation delay time), ten (Enable time), tdis (Disable time), tSK(O) (Skew (time), output), tr (Input rise time), tf (input fall time)

Can anyone please help.

Thanks & Regards,

Nanjunda M

  • 0
    TI__Guru 61910 points
    Hi Nanjunda,

    The LSF is passive device wherein the translation depends on the external pullup resistors. The input pullup resistors may or may not be used depending on the interface used.
    The tpd, rise time, fall time depends on the output loading and the pullup resistor used. the stronger pullup results in faster (smaller rise time). the fall time depends on the input driver ability to pull the line low.
    The tpd ( tplh and tphl) is given in the datasheet for different conditions.
  • 0 in reply to ShreyasRao
    Expert 2485 points

    Hi ShreyasRao,

    Thanks for the reply.

    I have attached the schematics below:

    We have a 511E pull-ups for a nominal current of about 5mA.

    Could you please let me know, how to calculate the tpd, raise time & fall times from the above data available.

    Thanks & Regards,

    Nanjunda M

  • 0 in reply to Nanjunda M
    TI__Guru 61910 points
    Nanjunda,

    Please watch the up translation video on LSF here:
    training.ti.com/TLM-LSF-Up

    This explains the use of pullup resistance and capacitive loading on the output rise time and hence the tpd.