Hey. I've been doing tolerance analysis on a circuit based around the INA226 and a colleague has asked me to double check the impact of input bias current offset and DC PSRR.
The circuit in question has two 10Ω resistors in series with the inputs as shown in figure 21 of the INA226 datasheet, so we'd like to ensure the difference in input bias currents wouldn't be a significant factor in the accuracy of the circuit.
Colleague also mentioned that while the power supply ripple is low and the PSRR is spec'd as 2.5uV/V, we're using a 3.3V power supply, and this could cause a constant offset of 3.3 * 2.5uV and throw off the accuracy of our measurement by 3 LSBs. Is this a well founded concern?
Outside of these factors, over a temperature variance of +/-30ºC, using a 0.01Ω sense resistor, I calculated a worst case of 0.38% accuracy at 1A. Does that seem like a reasonable tolerance for this part?
Thanks!
-MacLean
