So, I would like to make a square wave generator (any amplitude, about 50% duty cycle), where you could set a frequency from 370kHz to 1MHz.
I have found a solution to do that with 555 timer. Datasheet says it goes up to 3MHz.
For the 555 astable circuit I would use fixed R1 1kOhm and C 1pF. The R2 will vary from 720kOhm to 2MOhm.
Now the question is, is that C too small?
What could be a minimum R1 value?
R1, R2 and C are defined as here: http://www.ohmslawcalculator.com/555-astable-calculator
Also, is there any other simple way to do that?
I have found a solution to do that with 555 timer. Datasheet says it goes up to 3MHz.
For the 555 astable circuit I would use fixed R1 1kOhm and C 1pF. The R2 will vary from 720kOhm to 2MOhm.
Now the question is, is that C too small?
What could be a minimum R1 value?
R1, R2 and C are defined as here: http://www.ohmslawcalculator.com/555-astable-calculator
Also, is there any other simple way to do that?