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SN74LVCHR16245A and SN74LVCH16245A - the slew rate of the output

Hirotaka Matsumoto
Guru 27525 points
Other Parts Discussed in Thread: SN74LVCHR16245A, SN74LVCH16245A

Hi all

Would you mind if we ask SN74LVCHR16245A and SN74LVCH16245A?

How much is the slew rate of the output?
Of course, we know that you may not have these test data and these logic devices are defined propagation delay(tPLH or tPHL).
However, if you don't have these test data, do you have any calculation formula to evaluate the slew rate of the output?

We know Vcc, Icc and the load capacity, then is it possble to evaluate the value?

Kind regards,

Hirotaka Matsumoto

  • 0
    TI__Guru 56100 points
    Hi Hirotaka San ,

    The slew rate is the rate of change of output voltage . You can get that from the rise time Tr (10% to 90%) . you will have the change of voltage eg for 5V signal , delV = 4V(10% -90%) and delT =10ns (assuming) . Then 400V /uS is the slew rate for the device .
    The max slew rate is also calculated from 2*pi*f*V certain frequency . This calculation is mostly used for opamp devices but could be used for this too.
  • 0 in reply to ShreyasRao
    Guru 27525 points

    Shreyas Rao san

    Thank you for your so kind reply!

    We'd like to confirm one point that the max slew rate is also calculated from 2*pi*f*V certain frequency.
    In case of DC, the frequency is 0, isn't it?
    So, as the result, how should we get the slew rate?


    Kind regardss,

  • 0 in reply to Hirotaka Matsumoto
    TI__Guru 56100 points
    Hirotaka San ,

    Those specifically relate to Opamp BW calculations and again cant be applied to DC conditions .The slew rate as mentioned can be determined from tr (rise time) or tf (fall time )specs .