Relaxation oscillator

[coolstuff07]

Hello,

Can any one help how to calculate relaxation oscillator operating frequency.

I=10uA, C=5pf & reference voltage=1.17V.

Bye.

 

[betwixt]

With that information I would say the answer is probably about two months and 0.8 Km, in that order.

Brian.

 

[stefannm]

Assuming your capacitor has to charge from 0 to 1.17 twice for a total period. Or charge/discharge to these voltages.

i = C dv/dt
dt = C dv/i
dt = 5e-12 * 1.17 / 10e-6
dt = .585 us

Now to do this twice will be 2 * dt
2 dt = 1.170 us
=> f ~ 855.7kHz