What this 4-20 mA protector does for your loop
The MAX14626ETT+T is a current loop protector that sits in series with a 4-20 mA transmitter output, passing the loop current while clamping fault voltages that would otherwise damage the transmitter's output stage. It draws only 40 µA from the loop itself, so the transmitter's compliance voltage budget loses almost nothing to the protection circuit — important when the loop powers a 2-wire sensor at the far end of a long cable run.