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LTC2942 minimum voltage for coulomb counter

I am currently working on a design that uses a LTC2942 with an external sense resistor of 10 mOhms and battery pack with a large capacity (13200mAH @ 4.0V).
The LTC2942 is configured to use a prescaler of 64.

Sleep mode current is approximately 900uA which will give around 9uV drop across the sense resistor.
Running mode current 10mA - 300mA.
Charge current 2000mA.

At this stage the coulomb count does not seem to increment at all when the system is in sleep mode but the count is accurate when the system is running.

I have noticed in the datasheet on the Total Charge Error vs Differential Sense Voltage graph the error line starts at 0.2mV. 
I'm not sure if this is an indication of the minimum drop across the sense resistor that can be measured reliably.

My question is what is the minimum voltage across the sense resistor that can give reasonable results?


Fixed auto-corrected spelling
[edited by: broadaus at 6:26 AM (GMT 0) on 4 Mar 2019]