Texas Instruments INA2128UG4

Overview

INA2128UG4 from Texas Instruments is a dual, low-power instrumentation amplifier designed for precision DC-coupled signal conditioning in sensor front-ends. It delivers 50 µV max offset voltage, 0.5 µV/°C max drift, 120 dB min CMR at G ≥ 100, and operates from ±2.25 V to ±18 V supplies with 700 µA per channel quiescent current. It is used in high-accuracy industrial transmitters and medical ECG systems where input protection to ±40 V and stable gain over temperature are critical.

For engineers reviewing the INA2128UG4 datasheet, INA2128UG4 pinout, INA2128UG4 application, or INA2128UG4 equivalent, key selection criteria include guaranteed dual-channel matching, laser-trimmed RTI offset performance across –40°C to +85°C, SOIC-16 package compatibility with legacy layouts, and verified operation down to ±2.25 V supply rails without gain degradation.

Technical Context

The INA2128UG4 employs a three-op-amp architecture with current-feedback input stages, enabling 1.3 MHz bandwidth at G = 1 and maintaining 200 kHz at G = 100. Its internal laser-trimmed 50 kΩ feedback resistors set gain via a single external RG resistor (1–10,000 V/V), with gain error as low as ±0.005% for the U-grade variant.

Input protection circuitry withstands ±40 V differential and common-mode overvoltage independent of power state, while separate SenseA/SenseB feedback paths support remote load sensing. Channel crosstalk remains below –100 dB at 1 kHz due to fully isolated bias networks and layout-optimized internal routing.

Key Specifications

Pinout & Package

INA2128UG4 is housed in a 16-pin SOIC (DW) package measuring 10.3 mm × 10.3 mm, compatible with standard surface-mount assembly processes and IPC-7351B footprint DW_16.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA2128UG4, the INA2129UG4 provides superior DC accuracy but same footprint and supply compatibility, while the AD8226ARZ trades channel count, protection, and matching for lower unit cost and smaller size in non-critical applications.

Availability

INA2128UG4 is available at Aetrix Electronics and suitable for pressure transmitters, ECG monitors, and industrial weigh scales requiring stable component supply, long-term calibration integrity, and field-reliable input protection.

Supply support for INA2128UG4 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 expertise in precision signal chain solutions.

The INA2128UG4 belongs to TI's high-accuracy instrumentation amplifier product line, engineered specifically for industrial sensor signal conditioning where low drift, robust input protection, and dual-channel matching are mandatory.

FAQ

What is the maximum gain achievable with INA2128UG4?

The INA2128UG4 supports gains from 1 V/V to 10,000 V/V using a single external resistor (RG) connected between Pin 3 and Pin 11. The gain equation is G = 1 + (50 kΩ / RG). For G = 10,000, RG = 5 Ω; however, practical layout considerations (e.g., trace resistance, solder joint effects) limit reliable high-gain accuracy to RG ≥ 10 Ω. The INA2128UG4 datasheet confirms full specification compliance across this entire range under recommended operating conditions.

Does INA2128UG4 require external trimming for offset nulling?

No, the INA2128UG4 does not require external offset trimming in most applications. It is laser-trimmed at wafer level to deliver ≤50 µV max input offset voltage and ≤0.5 µV/°C max drift over –40°C to +85°C. Section 6.2.4 of the INA2128UG4 datasheet explicitly states that "most applications require no external offset adjustment." An optional trim circuit is provided only for systems demanding sub-10 µV residual offset after calibration.

Can INA2128UG4 operate from a single 5-V supply?

Yes, the INA2128UG4 supports single-supply operation from 4.5 V to 36 V, as specified in Section 5.3 of its datasheet. When powered from +5 V and ground, the input common-mode range is (V–) + 2 V to (V+) – 2 V, i.e., +2 V to +3 V, and output swing is limited to approximately +0.15 V to +4.85 V depending on CSO variant. Performance metrics such as CMR and bandwidth remain fully characterized and guaranteed across this configuration.

How does the input protection of INA2128UG4 function during power-down?

The INA2128UG4 input protection remains fully active even when power supplies are disconnected or turned off. Internal protection circuitry limits input current to ~1.5–5 mA during ±40 V overvoltage events, preventing damage regardless of supply state. This behavior is confirmed in Section 6.2.8 of the INA2128UG4 datasheet, which states: "The inputs are protected even if the power supplies are disconnected or turned off." No external components are needed to maintain this protection.

Is INA2128UG4 pin-compatible with other dual instrumentation amplifiers in SOIC-16?

The INA2128UG4 uses a proprietary pinout optimized for dual-channel operation with shared gain-setting and independent Sense/Ref paths. It is not pin-compatible with generic dual op-amps or other dual IAs like the AD8222 or INA286. Pin compatibility is confirmed only within the INA2128 family (e.g., INA2128U vs. INA2128UA); substitution requires schematic and layout revision to accommodate its unique RG, Sense, and Ref pin assignments.