4-20mA Current Transmitter with Sensor Excitation and Linearization

The XTR105 is a monolithic 4mA to

20mA, 2-wire current transmitter with two precision current sources. This device

provides complete current excitation for platinum RTD temperature sensors and

bridges, instrumentation amplifiers, and current output circuitry on a single

integrated circuit.

Versatile linearization circuitry

provides a 2nd-order correction to the RTD, typically achieving a 40:1 improvement

in linearity.

Instrumentation amplifier gain can be

configured for a wide range of temperature or pressure measurements. Total

unadjusted error of the complete current transmitter is low enough to permit use

without adjustment in many applications. This includes zero output current drift,

span drift, and nonlinearity. The XTR105 operates on loop power-supply voltages down

to 7.5V.

The XTR105 is available in DIP-14 and

SOIC-14 surface-mount packages and is specified for the industrial temperature range

of –40°C to +85°C.