The Texas Instruments XTR111 is a precision voltage-to-current converter designed for the standard 0mA–20mA or 4mA–20mA analog signals, and can source up to 36mA. The ratio between input voltage and output current is set by the single resistor RSET. The circuit can also be modified for voltage output.

EASY-TO-DESIGN INPUT/OUTPUT RANGES: 0mA–20mA, 4mA–20mA, 5mA–25mA AND VOLTAGE OUTPUTS
NONLINEARITY: 0.002%
LOW OFFSET DRIFT: 1μV/°C
ACCURACY: 0.015%
SINGLE-SUPPLY OPERATION
WIDE SUPPLY RANGE: 7V to 44V
OUTPUT ERROR FLAG (EF)
OUTPUT DISABLE (OD)
ADJUSTABLE VOLTAGE REGULATOR:
3V to 15V

4mA-to-20mA Current-Loop Communication

Current loop systems are used in electrically noisy industrial environments for sending analogue sensor data over long distances of 300m or more.