Original question:
How do I estimate the input bias current for a lower supply for example 3.3V? And how do I estimate the max bias current since the datasheet only specify typical? I am currently looking for similar current sense amp with comparator as INA301 but could not find one with low bias current.
Hello Sharina,
The input bias currents (IB) do not vary much with the supply voltage (VS) once VCM > Vs or VCM < Vs, where VCM is the common-mode input voltage of the input pins IN+/IN-. So if VCM is 12V, the input bias currents wont vary much over the entire operational VS range of 2.7V to 5.5V,
An appropriate estimate for the total maximum and minimum variation of IB at 25C is +/-15%.
The INA200-Q1 is a CSA with an internal comparator and its input bias current max out at 16uA. The INA200 uses the INA193 CSA so I have included the input bias curves from INA193 datasheet to show this. The only problem is the INA200-Q1 is not as accurate as the INA300-Q1.
The only other devices that have substantially lower IB are the INA190-Q1, INA191, INA186-Q1; however, they do not have internal comparators nor the speed of the INA300-Q1.
Sincerely,
Peter Iliya
Current Sensing Applications
