dear bastos,
if i have unity gain opamp.what should be its settling time in respect of UGB(open loop).
moreover how do you get the factor of 0.35 in your equation.
thanks for reply in advance.
dear bastos,
if i have unity gain opamp.what should be its settling time in respect of UGB(open loop).
moreover how do you get the factor of 0.35 in your equation.
thanks for reply in advance.
Hi.
tss = n*(1/ω-3dB) where n=ln(1/ess) and ess is small-signal steady-state error.
ω-3dB = βωu.
So by choosing a certain ess (it depends on accuracy or resolution you required) and tss (for a given clock rate) and β (for a given structure) you can find ωu and hence gm of your input devices. these are first steps in designing an opamp.
The above statements are correct, but all based on the assumption that the slew rate of the opamp is big enough. If the slew rate is not so big, then you should also do calculation for large signal