Shown on this slide is an illustration on how the MAX31865 cancels out cable resistance in three wire RTDs without requiring external current sinks. It measures the voltage across the FORCE+ wire, which is proportional to the resistance in the upper force lead. It also measures the voltage across the RTD, which includes the resistance in the lower force/sense lead. The device automatically subtracts those two values, leaving only the voltage across the RTD. The result is no current mismatch errors, with no external current sinks.