Texas Instruments INA126UAG4

Overview

INA126UAG4 from Texas Instruments is a single-channel, micropower instrumentation amplifier optimized for precision low-level differential signal acquisition in battery-powered and space-constrained systems. It delivers 250 µV max offset voltage, 3 µV/°C max drift, 35 nV/√Hz input voltage noise, ±1.35 V to ±18 V dual-supply operation, and gain programmable from 5 V/V to 10,000 V/V via a single external resistor - enabling high-accuracy sensor interfacing in portable ECG monitors and industrial transmitters.

For engineers reviewing the INA126UAG4 datasheet, INA126UAG4 pinout, INA126UAG4 application, or INA126UAG4 equivalent, this page provides verified technical context, package-specific pin functions, real-world application mappings, and validated alternative options - all grounded in TI's SBOS062D production datasheet (December 2025 revision).

Technical Context

The INA126UAG4 uses a two-op-amp topology that reduces quiescent current to 175 µA/channel while maintaining high input impedance (>1 GΩ) and balanced input structure - critical for unbalanced source impedances like thermocouples or bridge sensors. Its internal laser-trimmed 40 kΩ/10 kΩ resistor network enables precise gain setting via RG, with gain error as low as ±0.02% at G = 5.

It supports true single-supply operation (2.7 V to 36 V) using the REF pin for output level-shifting, and features integrated input protection diodes clamping signals to within ±0.7 V of supply rails. The device is specified across –40°C to +85°C and exhibits stable performance up to 1000 pF load capacitance.

Key Specifications

Pinout & Package

INA126UAG4 is supplied in an 8-pin SOIC (D) package with 1.27 mm pitch, 4.9 mm × 3.91 mm body, and exposed pad not present - suitable for automated SMT assembly and moderate-power dissipation (R_θJA = 116.4°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD620ARZ and INA333AIDR, the INA126UAG4 uniquely balances micropower operation (175 µA), wide supply range (±1.35 V), and programmable high gain (up to 10,000 V/V) - making it the only option among the three viable for portable, multi-range biomedical and industrial transmitters requiring both low power and high signal fidelity.

Availability

INA126UAG4 is available at Aetrix Electronics and suitable for electrocardiogram (ECG) monitoring, industrial level transmitter conditioning, multiparameter patient monitor front-ends, and AC charging station current sensing requiring stable component supply, long-term lifecycle assurance, and traceable sourcing.

Supply support for INA126UAG4 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 over 50 years of precision amplifier innovation and ISO 9001-certified manufacturing.

The INA126UAG4 belongs to TI's INAx126 micropower instrumentation amplifier product line, designed specifically for high-accuracy, low-power sensor signal conditioning in portable medical devices, industrial process transmitters, and battery-operated test equipment.

FAQ

What is the maximum gain achievable with INA126UAG4, and how is it set?

The INA126UAG4 supports gains from 5 V/V to 10,000 V/V using a single external resistor (RG) connected between pins 1 and 8. Gain is calculated as G = 5 + (80 kΩ / RG). For G = 10,000 V/V, RG = 8.0 Ω (7.87 Ω 1% standard value); the INA126UAG4 datasheet confirms this range is fully characterized and supported across its operating temperature range.

Does INA126UAG4 support true single-supply operation, and what is required?

Yes, the INA126UAG4 operates from a single 2.7 V to 36 V supply. To achieve linear output swing, the REF pin (pin 5) must be driven by a low-impedance source - typically tied to mid-supply (e.g., VCC/2) via a precision voltage divider or buffered reference. TI specifies that >80 dB CMRR requires ≤8 Ω source impedance at the REF pin, as confirmed in SBOS062D Section 7.2.

What is the input bias current path requirement for INA126UAG4, and why does it matter?

The INA126UAG4 has input bias current of ±25 nA maximum flowing *out* of both inputs. A DC return path must be provided - e.g., equal 47 kΩ resistors from each input to REF or ground - to prevent input saturation. Without this path, floating inputs exceed common-mode range, causing invalid output. This requirement is explicitly detailed in TI's Figure 7-3 and Section 7.2.2.3.

How does the INA126UAG4 handle input overvoltage conditions?

The INA126UAG4 integrates internal ESD diodes from each input to V+ and V– rails, clamping input voltages to within approximately ±0.7 V of the supply rails. If input signals may exceed this range (e.g., from 24 V field sensors), a series current-limiting resistor must restrict input current to <10 mA - a design requirement clearly stated in Section 5.1 Absolute Maximum Ratings and Section 7.2.2.5.

Is the INA126UAG4 RoHS-compliant and lead-free?

Yes, the INA126UAG4 is RoHS-compliant and lead-free, as documented in Texas Instruments' official packaging information (Section 10, Mechanical, Packaging, and Orderable Information, SBOS062D). The "G4" suffix denotes green (lead-free) packaging per TI's standardized part numbering convention.