Texas Instruments XTR106UA

Overview

XTR106UA from Texas Instruments is a monolithic 4mA to 20mA two-wire current transmitter optimized for bridge sensor conditioning, featuring integrated 2.5V/5V bridge excitation references, 5.1V regulator output, ±50 µA zero-output initial error (–40°C to +85°C), and ±25 ppm/°C max span drift - deployed in industrial pressure transmitters and HART-compatible field instrumentation.

For engineers reviewing the XTR106UA datasheet, XTR106UA pinout, XTR106UA application, or XTR106UA equivalent, this page delivers verified package mapping (14-pin SOIC), confirmed linearization architecture (RLIN/Lin Polarity-controlled second-order correction), real-world bridge nonlinearity compensation capability (up to ±5% with 5V reference), and validated alternative selection guidance for cost-optimized 4–20mA loop design.

Technical Context

The XTR106UA implements a precision instrumentation amplifier with externally set gain (RG pins 3–4), dual programmable bridge excitation (VREF2.5 at pin 13, VREF5 at pin 14), and analog linearization via RLIN (pin 11) and Lin Polarity (pin 12) to dynamically modulate reference voltage and correct parabolic sensor nonlinearity. Its current output stage drives an external NPN transistor (B/E pins 9/8) to maintain low junction temperature in the IC core while delivering up to 20mA loop current.

Operation requires loop supply (V+ at pin 10, 7.5V–36V), local return (IRET at pin 6), and differential input (VIN+ at pin 5, VIN– at pin 2). The device achieves high accuracy through matched internal resistor networks, 86dB min CMRR, 110dB min PSRR, and guaranteed performance over –40°C to +85°C (operable to +125°C).

Key Specifications

Pinout & Package

Package: 14-pin SOIC (D package), 8.65mm × 6mm body size, surface-mount compatible, rated for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 4–20mA current transmitter applications.

Compared with XTR106UA, XTR116IRUGR offers smaller size and lower quiescent current but omits critical bridge-specific features; INA220AIDRCT provides digital precision but requires full redesign to implement 4–20mA output, making neither suitable for direct substitution in bridge transmitter designs.

Availability

XTR106UA is available at Aetrix Electronics and suitable for industrial process control, factory automation, and field transmitter applications requiring stable component supply, long-lifecycle support, and traceable sourcing for safety-critical deployments.

Supply support for XTR106UA includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with decades of heritage in precision signal conditioning and industrial interface solutions.

The XTR106UA belongs to TI's XTR series of 4–20mA current transmitters, designed specifically for cost-optimized, high-accuracy bridge sensor signal conditioning in harsh industrial environments.

FAQ

What is the primary function of the XTR106UA in a 4–20mA transmitter design?

The XTR106UA serves as a complete analog front-end for bridge sensors, integrating differential instrumentation amplification, selectable 2.5V/5V bridge excitation, second-order analog linearization, 5.1V auxiliary regulation, and 4–20mA loop drive capability. It eliminates discrete op-amps, references, and linearization circuitry - enabling compact, high-stability field transmitter designs without calibration in many cases. The XTR106UA is engineered to deliver low unadjusted error and robust performance across industrial temperature ranges.

How does the XTR106UA achieve bridge linearization, and what is the maximum correctable nonlinearity?

The XTR106UA corrects parabolic bridge nonlinearity by dynamically varying the bridge excitation voltage using the RLIN (pin 11) and Lin Polarity (pin 12) inputs. This adds a second-order term to the transfer function, improving linearity up to 20:1 versus an uncompensated bridge. With the 5V reference, it corrects up to ±5% full-scale nonlinearity; with the 2.5V reference, it handles +5%/–2.5% nonlinearity. The XTR106UA requires known sensor nonlinearity (B) to calculate RLIN and adjusted RG values per TI's published equations.

Can the XTR106UA operate without an external transistor, and what is its maximum output current capability?

No - the XTR106UA requires an external NPN transistor (e.g., TIP29C) connected between V+ (pin 10), B (pin 9), and E (pin 8) to handle the majority of loop current dissipation. The IC itself drives only the base current; the external transistor conducts the full 4–20mA (up to 28mA overscale) loop current. This architecture isolates heat from the precision analog core, preserving offset and drift performance. Without the external transistor, the XTR106UA cannot sustain 20mA output reliably or meet its specified error limits.

What are the key differences between the XTR106UA and the XTR106PA variants?

The XTR106UA and XTR106PA share identical functionality and pinout but differ in initial accuracy specifications: the XTR106UA has ±50 µA zero-output initial error (vs ±25 µA for XTR106PA) and ±0.4% untrimmed span error (vs ±0.2% for XTR106PA). Both exhibit identical drift performance (±25 ppm/°C span drift, ±0.25 µV/°C offset drift) and operate across the same –40°C to +85°C temperature range. The XTR106UA is optimized for cost-sensitive applications where minor initial error is acceptable post-calibration or within system tolerance.

Is the XTR106UA compatible with HART communication, and how is that supported?

Yes - the XTR106UA is explicitly designed for HART-compatible field transmitters. Its 5.1V VREG output (pin 1) supplies regulated power to external HART modems, while its wide 7.5V–36V loop supply range and high PSRR (110dB min) ensure immunity to HART's 1mA peak AC signal superimposed on the 4–20mA DC loop. The device's low noise (0.6 µVpp input noise) and stable common-mode rejection prevent HART signal corruption. TI provides reference schematics showing direct integration of HART ICs with the XTR106UA's VREG and IRET rails.