OPA365: OPA365 Input Impedance

Hi Roland,

the input bias current is such extremely low, that the input impedance is entirely dominated by the input capacitance. Even at low frequencies the input current flowing caused by the input capacitance is decades higher than the static input bias current.

Also, if you have a look at figure 6 of datasheet, you can see that there's almost no variation of input bias current with input voltage at Vcm=Vcc/2. And it's hard to estimate whether you can apply the Ohm's law, at all. In such a situation in datasheet only the input capacitance and the input bias current is given but no input resistance.

Kai

Hi Roland,

The OPA365 device has CMOS inputs with > 1Tohms or 10^12 ohm input impedance. That's the reason why the input bias current is very low on the order of +/-10pF max.

Best Regards,
Rohit