INA169：Detection current range issue!

David, 

I am assuming that the 0m50 resistor here for RS is 0.5mΩ, or 500uΩ. With your defined system, your maximum differential occurs at 60 amps, where V_sense would be

V_sense = 60A * 0.5mohm =  30mV

and you want that value to correspond to your highest voltage output for maximization of FSR, so ideally,

Vout = 3.3 V when V_sense = 30 mV. To achieve this, we need to select a gain for the design to achieve this, so

3.3V/.030V = 110. So a 110kΩ resistor for RL would cast the sense voltage across the entirety of the output. You can still use 22kΩ, but this would only use a portion of the output range, and also the offset voltage will be larger in proportion to the total signal. 

Hope this helps. Let me know if you need anything else.

Carolus