Texas Instruments XTR117AIDGKRG4

Overview

XTR117AIDGKRG4 from Texas Instruments is a precision 4–20mA current-loop transmitter IC designed for two-wire industrial sensor signal conditioning. It features 100× current gain (IO = 100 × IIN), ±0.05% span error, 130µA quiescent current, and integrated 5V regulator - enabling direct powering of external circuitry while maintaining accurate loop current control via IRET-referenced return path. It operates across –40°C to +125°C in VSSOP-8 packaging for field transmitter applications.

For engineers reviewing the XTR117AIDGKRG4 datasheet, XTR117AIDGKRG4 pinout, XTR117AIDGKRG4 application, or XTR117AIDGKRG4 equivalent, key selection criteria include its low-quiescent-current operation in 7.5V–36V loop supplies, IRET-sensed local ground architecture for external sensor biasing, and compatibility with discrete NPN transistors for high-voltage loop compliance - critical for flow, temperature, and pressure transmitter designs requiring long-cable immunity and HART-capable stability.

Technical Context

The XTR117AIDGKRG4 implements a fixed-gain (100 A/A) current-input transconductance architecture where input current at IIN directly sets output current IO = 100 × IIN, referenced to IRET. Its internal 5V regulator powers external circuitry (e.g., sensor bridges, ADCs, references), with all regulator current returned through IRET to preserve output accuracy.

It requires an external NPN transistor (Q1) connected between V+ and IO pins to handle full-scale power dissipation, decoupling thermal effects from the precision core. The device operates in a single functional mode within 7.5V–36V loop supply and –40°C to +125°C ambient, with no digital interface or configuration registers - relying on passive resistor networks (e.g., RIN, RLIM) for scaling and offset.

Key Specifications

Pinout & Package

The XTR117AIDGKRG4 is packaged in an 8-pin VSSOP (DGK) package measuring 3mm × 4.9mm, with exposed thermal pad on underside recommended to be connected to IRET for optimal thermal performance and noise immunity.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XTR115IDGKR and XTR116IDRBR, the XTR117AIDGKRG4 delivers the lowest quiescent current (130µA), smallest VSSOP-8 footprint, and simplest BOM by omitting secondary references - making it optimal for cost-sensitive, power-constrained, or space-limited field transmitters where only 5V bias is required.

Availability

XTR117AIDGKRG4 is available at Aetrix Electronics and suitable for pressure transmitter, temperature transmitter, flow transmitter, and PLC analog input module applications requiring stable component supply across extended temperature and long-lifecycle industrial deployments.

Supply support for XTR117AIDGKRG4 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 company headquartered in Dallas, Texas, specializing in analog and embedded processing technologies with broad industrial, automotive, and communications product portfolios.

The XTR117AIDGKRG4 belongs to TI's precision current-loop transmitter family, engineered specifically for ruggedized two-wire 4–20mA field instrumentation where low power, high accuracy, and thermal resilience are mandatory.

FAQ

What is the function of the IRET pin on the XTR117AIDGKRG4?

The IRET pin on the XTR117AIDGKRG4 serves as the local ground return for the internal 5V regulator (VREG) and any external circuitry powered by it. All current drawn from VREG must return through IRET to prevent injection of error current into the 4–20mA output loop - a critical design requirement to maintain the specified ±0.05% span accuracy. In PCB layout, IRET should be tied directly to the thermal pad and star-grounded near the XTR117AIDGKRG4.

Can the XTR117AIDGKRG4 operate without an external transistor?

The XTR117AIDGKRG4 can operate without an external transistor only at very low loop voltages (<12V) and currents (<4mA), as its internal output stage lacks sufficient voltage compliance and power handling. For standard 24V loops and full 20mA output, an external NPN transistor (e.g., TIP29C, FCX690BTA) is mandatory - connected between V+ (collector) and IO (emitter) - to dissipate heat externally and avoid thermal-induced gain drift in the XTR117AIDGKRG4 core.

What is the maximum load resistance supported by the XTR117AIDGKRG4 at 24V loop supply?

At 24V loop supply, the XTR117AIDGKRG4 supports a maximum load resistance of 1.1kΩ while maintaining 20mA output - calculated as (24V − 7.5V minimum compliance) ÷ 20mA = 825Ω, with practical margin yielding ≤1.1kΩ depending on external transistor V_CE(sat). This accommodates standard 250Ω receiver resistors plus cable impedance and HART communication components, provided the external transistor is selected for low saturation voltage and adequate power rating.

How does the XTR117AIDGKRG4 achieve 4mA low-end offset?

The XTR117AIDGKRG4 achieves 4mA low-end offset by leveraging its 130µA quiescent current and external resistor network: a 40µA input current (IIN) at Pin 2 produces 4mA output (IO = 100 × IIN). This 40µA is typically generated using a precision reference (e.g., REF3425) and resistor divider - such as 2.475kΩ from 2.5V reference to IIN - with IRET as the return node. VREG may serve as a lower-accuracy alternative reference source.

Is the XTR117AIDGKRG4 compatible with HART communication?

Yes, the XTR117AIDGKRG4 supports HART communication when configured with appropriate filtering: a 2–3nF capacitor between V+ and IO pins is recommended instead of the default 10nF to preserve >1.2kHz HART signal bandwidth while maintaining loop stability. Its low 130µA quiescent current and minimal internal noise (0.6µVpp, 0.1Hz–10Hz) ensure clean superposition of the 1.2/2.2kHz FSK signal onto the 4–20mA DC loop current without distortion or demodulation errors.