XTR115/XTR116 pdf datasheet (4

The XTR115 and XTR116 are precision current output
converters designed to transmit analog 4-to-20mA
signals over an industry standard current loop. They
provide accurate current scaling and output current
limit functions.
The on-chip voltage regulator (5V) can be used to
power external circuitry. A precision on-chip VREF
(2.5V for XTR115 and 4.096V for XTR116) can be
used for offsetting or to excite transducers. A current
return pin (IRET) senses any current used in external
circuitry to assure an accurate control of the output
current.
The XTR115 is a fundamental building block of
smart sensors using 4-to-20mA current transmission.
The XTR115 and XTR116 are specified for operation
over the extended industrial temperature range,
–40°C to +85°C.