Hello to all.
I am looking for the maximum frequency of pulse that I can apply to input pins of the gate 74HC08.
How can I calculate that?
Very thank you.
The datasheet says transition time 7ns, propagation delay 11ns typical at 5V
So you can assume after 18ns the output has completed responding to an input, indicating 25MHz
would work fine (and it will probably handle higher, since propagation delay isn't strictly speaking
a limit on bandwidth.
[ Oops, that was for the 74HCT08, the figures are 7ns and 7ns for the 74HC08, ie 35MHz ought
to be doable (again, that's typical, you might want to play safe a bit) ]
How about LM324. Actually I would like to use LM324 as a Buffer in my circuit. How could I calculate the input signal frequency that I can apply to it?
Thanks again.
There are two specs of interest for this, unity gain bandwidth (the frequency at which the open-loop gain
falls to 1), and the slew-rate (maximum dV/dt on the output).
For the LM324 I inferred the slew rate from the large signal response graph as 0.5V/us, and the unity
gain is at 1MHz.
This means you can't get more than unity gain at 1MHz, x10 gain at 100kHz, x100 gain at 10kHz, etc.
Its a low speed opamp, basically, especially given that low slew rate on the output, which will dominate.