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SN7407: SN7407 input to output logic clarification required

Chetan Patel
Prodigy 140 points

Part Number: SN7407
Other Parts Discussed in Thread: SN7406, CD40109B

We want to use SN7407 logic Ic in one of our Application where we want to convert 5V signal to 15V signal with invert.

Our requirement is that SN7407 Input signal is  5V level PWM signal and our requirement from output after connected to 10K pull up resistor with 15V supply is inverted output signal with 15V level as given 5V input signal.

So for our application it is Ok to use SN7407 IC?

Regards,

Chetan Patel

  • 0
    Guru 325800 points

    The SN7407's outputs are rated for 30 V. But it does not invert the signal; you would have to use the SN7406 instead.

    The CD40109B is a (non-inverting) level shifter that does not require pull-up resistors.

  • 0 in reply to Clemens Ladisch
    Prodigy 140 points

    Dear Clemens,

    Thanks for your reply.

    CD40109B having propagation delay > 200ns. we require propagation delay of <50ns.

    As per your reply we can use SN7406 IC for our application of signal inversion and as shown in  SN7406 datasheet Propagation delay at 270R load resistor is < 25nS.

    We required information that  if we increase load resistor to 10K then what will be propagation delay.

    Regards,

    Chetan Patel

  • 0 in reply to Chetan Patel
    TI__Mastermind 47895 points

    Hey Chetan,

    Propagation delay is measured from 50% of the input signal to 50% of the output signal. Since you are pulling up to 15 V instead 5V this would be additional delay. On top of that, the High transition at the output is determined by the pull-up value as well as the load capacitance. With these variables impacting the measurement of the propagation delay, I recommend grabbing an EVM for the device and some samples so you can measure this with you system parameters.