Texas Instruments INA105KUE4

Overview

INA105KUE4 from Texas Instruments is a precision unity-gain differential amplifier IC designed for high-accuracy signal conditioning in measurement and feedback circuits. It delivers 72dB minimum CMRR, 0.025% maximum gain error, and ±20μV/°C offset drift, operating on ±5V to ±18V supplies. It is used in battery cell formation equipment, servo position feedback, and level transmitters where precise differential voltage subtraction is required.

For engineers reviewing the INA105KUE4 datasheet, INA105KUE4 pinout, INA105KUE4 application, or INA105KUE4 equivalent, key selection criteria include guaranteed CMRR over temperature, laser-trimmed resistor matching, rail-to-rail common-mode input range (±20V at ±15V supply), and SOIC-8 packaging compatibility with industrial PCB layouts.

Technical Context

The INA105KUE4 integrates a precision bipolar op amp with four laser-trimmed 25kΩ metal-film resistors to form a monolithic unity-gain difference amplifier. Its internal resistor network ensures ratio-matched tracking (low TCR) across temperature, directly enabling stable CMRR and gain accuracy without external precision components.

It operates in a single functional mode: fixed G = 1 differential configuration with reference input (pin 1) for output offset nulling. Input common-mode range extends beyond supply rails (±20V at ±15V), enabled by internal resistor division before the op amp inputs - not rail-to-rail input stage operation.

Key Specifications

Pinout & Package

INA105KUE4 is supplied in an 8-pin SOIC (Small Outline Integrated Circuit) package measuring 4.90 mm × 6.00 mm, optimized for surface-mount assembly and thermal performance (R_θJA = 108.9°C/W).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision differential amplifier applications.

Compared with INA105KUE4, INA106U provides higher gain and bandwidth but reduces usable input range, while AD629ARZ offers superior CMRR and high-voltage tolerance at the cost of lower DC precision and higher quiescent current - making INA105KUE4 optimal for industrial DC-coupled differential sensing below ±20 V CM.

Availability

INA105KUE4 is available at Aetrix Electronics and suitable for battery test systems, servo feedback loops, and industrial level transmitters requiring stable component supply, long-term calibration retention, and SOIC-8 manufacturability.

Supply support for INA105KUE4 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 amplifiers and data acquisition solutions.

The INA105 belongs to TI's precision instrumentation amplifier family, engineered specifically for high-accuracy, low-drift differential signal conditioning in industrial test, measurement, and control systems.

FAQ

What is the maximum common-mode input voltage supported by the INA105KUE4?

The INA105KUE4 supports a common-mode input voltage range of ±20 V when operated on ±15 V supplies. This extended range is achieved via internal 25kΩ resistor division before the op amp inputs, allowing direct interface with high-voltage sensor bridges and industrial field signals without external attenuation. Operation outside this range risks damage or degraded CMRR.

Can the INA105KUE4 be used with a single supply?

Yes, the INA105KUE4 can operate from a single supply (e.g., 10 V to 36 V), but its input common-mode and output swing ranges become asymmetric. For example, with +30 V and GND supplies, the usable common-mode range shifts toward mid-rail. Reference pin (Pin 1) must be biased appropriately, and output swing is limited to ~10 V to ~20 V. Dual supply is recommended for full symmetric performance.

What is the purpose of the Sense pin (Pin 5) on the INA105KUE4?

The Sense pin (Pin 5) connects to a 25kΩ resistor tied to the op amp's inverting input. It enables advanced configurations such as precision current sensing, summing amplifiers, and gain-adjustable topologies (e.g., G = 1 + 2R_f/R₁). Unlike the standard –In pin, Sense allows independent signal injection into the feedback path without disturbing the primary differential input node - critical for instrumentation-grade circuit flexibility.

How does the INA105KUE4 achieve 72 dB minimum CMRR over temperature?

The INA105KUE4 achieves guaranteed 72 dB minimum CMRR over –40°C to +85°C through laser trimming of its on-chip 25kΩ resistor network and matched physical layout that minimizes temperature coefficient (TCR) mismatch. This ensures resistor ratios remain stable across temperature, directly preserving gain accuracy and common-mode rejection - unlike discrete resistor implementations where TCR differences dominate drift.

Is the INA105KUE4 pin-compatible with other members of the INA105 family?

Yes, the INA105KUE4 shares identical SOIC-8 pinout and electrical behavior with all INA105 variants (e.g., INA105KP, INA105AM). Differences lie only in grade-specific parameters: KU/KP grades specify 500 μV max offset and 72 dB min CMRR, while AM/BM grades offer tighter specs (50 μV offset, 80 dB CMRR). All share identical pin functions, package dimensions, and application circuitry.