XTR112U

Overview

The XTR112U is a monolithic 4-20mA two-wire current transmitter manufactured by Texas Instruments, originally developed by Burr-Brown. It integrates precision current sources for RTD or bridge excitation, an instrumentation amplifier, and linearization circuitry on a single chip. The device operates on loop supply voltages ranging from 7.5V to 36V. It features low unadjusted error, high power supply rejection (110dB min), and high common-mode rejection (86dB min). The XTR112U includes two 250µA matched current sources for sensor excitation and provides second-order RTD linearization correction.

Feature Summary

• Integrates complete current excitation, instrumentation amplifier, and output circuitry for platinum RTD sensors and bridges.
• Provides versatile linearization circuitry that typically achieves a 40:1 improvement in linearity through second-order correction.
• Features extremely low offset drift of 0.4µV/°C and high power supply rejection ratio of 110dB minimum.

Applications

• Industrial process control systems requiring precise signal transmission.
• Factory automation environments utilizing remote temperature and pressure transducers.
• SCADA remote data acquisition networks needing robust 4-20mA loop interfaces.

Procurement Notes

Verify the specific ordering suffix 'U' corresponds to the SO-14 surface-mount package variant. Confirm the manufacturer source is Texas Instruments, as they acquired the original Burr-Brown product line. Ensure the component meets the specified industrial temperature range of -40°C to +85°C for your deployment environment.

Selection Notes

Select the XTR112U when two 250µA precision current sources are required for RTD excitation. This model is suitable for applications demanding high accuracy without external adjustment due to its low total unadjusted error. Consider the XTR114 if lower 100µA excitation currents are preferred for specific sensor types.

Part Context

The XTR112U belongs to the XTR112/XTR114 family of precision current transmitters. These devices were originally produced by Burr-Brown Corporation before being integrated into Texas Instruments' portfolio. They are designed to replace discrete solutions for 4-20mA loop transmission, offering significant space savings and improved performance characteristics.

Replacement Considerations

The XTR114U serves as a functional alternative within the same series, differing primarily in the magnitude of its internal excitation current sources (100µA versus 250µA).