4-20mA, Two-Wire Transmitter 'Smart' Programmable with Signal Conditioning

The XTR108 is a "smart", programmable, 4-20mA, two-wire transmitter designed for temperature and bridge sensors. Zero, span, and linearization errors in the analog signal path can be calibrated via a standard digital serial interface, eliminating manual trimming. Non-volatile ex-ternal EEPROM stores calibration settings.

The all-analog signal path contains an input multiplexer, autozeroed programmable-gain instrumentation amplifier, dual programmable current sources, linearization circuit, voltage reference, sub-regulator, internal oscillator, control logic, and an output current amplifier. Programmable level shifting compensates for sensor DC offsets. Selectable up- and down-scale output indicates out-of-range and burn-out per NAMUR NE43. Automatic reset is initiated when supply is lost.