I want to make a 72 minute timing output on QM(#2) using SN74HC4060.
The prerequisites are fixed at C1=0.22uF, R2=1M, and I want to adjust R1 so that a timing output of 72 minutes can be obtained.
If you use the commonly known formula 1, R1=1.918M is calculated.
formula 1] T=2^n/fosc (fosc=1/2.5(R1xC1))
When substituting into the formula 2 in the data sheet, R1= 2.2M is calculated.
formula 2] T=2^n/fosc (fosc=0.455/(R1xC1))
Substituting another formula 3 in the data sheet, R1=3.02M is calculated.
formula 3] T=2^n/fosc (fosc=1/(2R1xC1x((0.405xR2)/(R1+R2))+0.693)
Since there is no current simulation tool, we are asking here.
Which calculation formula should I design so that I can see the output that fits the 72 minutes I want?
What should I write the value of R1 as?
