Texas Instruments XTR116UA/2K5G4

Overview

XTR116UA/2K5G4 from Texas Instruments is a precision 4–20 mA current-loop transmitter IC designed for industrial sensor signal conditioning and loop-powered field transmitters. It features a 4.096 V reference output, 5 V regulator, 100× current gain, ±0.05% span error, and operates across –40°C to +85°C in a SOIC-8 package - enabling accurate voltage-to-current conversion in two-wire analog sensor interfaces.

For engineers reviewing the XTR116UA/2K5G4 datasheet, XTR116UA/2K5G4 pinout, XTR116UA/2K5G4 application, or XTR116UA/2K5G4 equivalent, key selection criteria include reference voltage accuracy (±0.05% typ), quiescent current (200 µA), loop supply range (7.5 V to 36 V), thermal stability (±20 ppm/°C VREF drift), and compatibility with HART modulation in process automation systems.

Technical Context

The XTR116UA/2K5G4 implements a precision current-input architecture with fixed 100× transconductance gain (IO = 100 × IIN), where input current flows into pin 2 and is mirrored to the loop output via an external NPN transistor connected to pins 5 (E) and 6 (B). Its internal 4.096 V reference (pin 1) and 5 V regulator (pin 8) are independently buffered and require return current through IRET (pin 3) to maintain output current accuracy.

Operation relies on a low-quiescent-current amplifier stage and external transistor-based current amplification to minimize on-die self-heating errors. The device supports linear output up to 25 mA with internal over-scale limiting at ~32 mA, and requires careful capacitive load compensation on VREF for stable operation with sensor excitation circuits.

Key Specifications

Pinout & Package

Package: SOIC-8 (D), 4.90 mm × 3.90 mm, surface-mount, leaded plastic body.

Key Features

Applications

Equivalent & Alternatives

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

Compared with XTR116UA/2K5G4, the XTR116U/2K5 offers lower cost but reduced process-site coverage and tighter spec guarantees, while the XTR117UA/2K5 removes VREF functionality to reduce complexity and layout overhead - making it suitable for streamlined current-loop designs without integrated excitation needs.

Availability

XTR116UA/2K5G4 is available at Aetrix Electronics and suitable for temperature transmitters, flow transmitters, PLC analog input modules, and two-wire smart sensors requiring stable component supply, long-term lifecycle support, and guaranteed industrial temperature performance.

Supply support for XTR116UA/2K5G4 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, embedded processing, and high-reliability components for industrial, automotive, and communications markets.

The XTR116UA/2K5G4 belongs to TI's XTR family of precision 4–20 mA current-loop transmitters, engineered specifically for robust, low-power, two-wire field instrumentation in harsh industrial environments.

FAQ

What is the reference voltage output of the XTR116UA/2K5G4?

The XTR116UA/2K5G4 provides a precision 4.096 V reference voltage on pin 1 (VREF), with typical accuracy of ±0.05% and temperature coefficient of ±20 ppm/°C over –40°C to +85°C. This voltage is intended for sensor excitation or offset generation and must have its return current routed through the IRET pin (pin 3) to preserve output current accuracy. It is distinct from the XTR115's 2.5 V reference and is not used internally by the IC.

How does the XTR116UA/2K5G4 achieve 4–20 mA output with only 200 µA quiescent current?

The XTR116UA/2K5G4 achieves 4–20 mA output using a 100× current gain architecture: a 40 µA–200 µA input current (IIN) applied to pin 2 is amplified to produce 4 mA–20 mA at the IO pin. Its 200 µA quiescent current establishes the minimum possible loop current, allowing up to ~3.7 mA of additional current to power external circuitry (e.g., op-amps, ADCs) while still meeting the 4 mA live-zero requirement - all within the 7.5 V–36 V loop supply range.

Can the XTR116UA/2K5G4 be used with HART communication?

Yes, the XTR116UA/2K5G4 is compatible with HART communication. To ensure signal integrity, use a 2 nF–3 nF bypass capacitor between V+ and IO (instead of the default 10 nF) to avoid attenuating the 1.2 kHz/2.2 kHz HART frequency tones. The device's low noise (0.6 µVpp, 0.1 Hz–10 Hz) and stable 100× gain support clean superposition of digital FSK signals onto the analog 4–20 mA loop without introducing significant jitter or distortion.

What external transistor is recommended for the XTR116UA/2K5G4?

Texas Instruments recommends NPN transistors such as the TIP29C, FCX690BTA, or MMBTA28-7-F for use with the XTR116UA/2K5G4. These devices provide sufficient voltage rating (>40 V), current capability (>500 mA), and thermal performance for 20 mA loop operation at up to 36 V supply. The XTR116UA/2K5G4 drives the transistor's base (pin 6) and emitter (pin 5); MOSFETs are not recommended due to lack of accuracy improvement and potential gate-drive complications.

Does the XTR116UA/2K5G4 require external compensation when driving capacitive loads on VREF?

Yes, the XTR116UA/2K5G4 requires external compensation when driving capacitive loads on the VREF pin (pin 1). For stable operation, TI specifies two capacitor configurations: either a high-frequency capacitor (CHF = 10 pF–0.5 µF) with series isolation resistor (RISO), or CHF with snubber network (RCOMP = 50 Ω, CLF = 2.2 µF–22 µF). Failure to apply proper compensation may cause oscillation or reference voltage instability, especially when powering capacitive sensor bridges or ADC reference inputs.