Texas Instruments INA2128U/1K

Overview

INA2128U/1K from Texas Instruments is a dual, low-power instrumentation amplifier designed for precision signal conditioning in sensor front-ends. It delivers 50 µV max offset voltage, 0.5 µV/°C max drift, 1.3 MHz bandwidth at G=1, 120 dB min CMR, and ±40 V input protection-enabling high-accuracy measurement in industrial transmitters and medical ECG systems.

For engineers reviewing the INA2128U/1K datasheet, INA2128U/1K pinout, INA2128U/1K application, or INA2128U/1K equivalent, key selection criteria include dual-channel matched performance, laser-trimmed DC accuracy, current-feedback architecture for stable high-gain bandwidth, and SOIC-16 packaging compatible with space-constrained analog input modules.

Technical Context

The INA2128U/1K implements a three-op-amp current-feedback topology that maintains 200 kHz bandwidth even at G = 100-critical for dynamic sensor signals without sacrificing DC precision. Its laser-trimmed internal 50 kΩ feedback resistors ensure gain accuracy of ±0.024% at G = 1 and ±0.17% at G = 100 (CSO: TID), while separate SenseA/SenseB terminals enable remote output sensing for load-compensated accuracy.

Input protection circuitry withstands ±40 V continuously-even with supplies off-while maintaining 10 GΩ differential input impedance and 100 GΩ common-mode impedance. The device operates from ±2.25 V to ±18 V dual supply or 4.5 V to 36 V single supply, with quiescent current held to 700 µA per channel for battery-powered DAQ systems.

Key Specifications

Pinout & Package

INA2128U/1K is housed in a 16-pin SOIC (DW) package measuring 10.3 mm × 10.3 mm, with standard JEDEC MS-012AC footprint and 1.27 mm pitch. Thermal resistance R_θJA is 110°C/W, supporting operation up to +85°C ambient without forced airflow.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA2129U/1K, the INA2128U/1K trades 0.3 µV/°C higher drift for broader supply range (±2.25 V vs ±5 V min) and lower cost; versus AD8422ARZ, it provides dual-channel integration and robust field-rated protection at the expense of bandwidth and noise floor.

Availability

INA2128U/1K is available at Aetrix Electronics and suitable for pressure transmitters, temperature transmitters, and weigh scale systems requiring stable component supply across extended industrial temperature ranges and multi-year production cycles.

Supply support for INA2128U/1K 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 INA2128U/1K belongs to TI's instrumentation amplifier product line, engineered specifically for high-accuracy, low-power sensor signal conditioning in industrial process control, medical diagnostics, and test equipment.

FAQ

What is the maximum gain achievable with INA2128U/1K, and how is it set?

The INA2128U/1K supports gains from 1 to 10,000 V/V using a single external resistor (RG) connected between pins 6 and 14. Gain is calculated as G = 1 + (50 kΩ / RG). For G = 10,000, RG = 5 Ω - requiring careful layout to minimize parasitic resistance. At this gain, bandwidth drops to 20–33 kHz depending on chip site origin (CSO: SHE or TID), and gain error rises to ±1% max. The INA2128U/1K datasheet specifies performance across this full range under defined test conditions.

Does INA2128U/1K require external offset trimming in typical applications?

No, the INA2128U/1K does not require external offset trimming in most applications due to laser trimming that achieves 50 µV max input offset voltage and 0.5 µV/°C max drift. Only high-precision systems demanding sub-10 µV residual offset-such as metrology-grade calibrators-may benefit from optional trimming circuits using the REF pins. The INA2128U/1K's internal trimming eliminates factory calibration steps for 95% of industrial sensor interfaces.

How does the input protection of INA2128U/1K behave during power-down conditions?

The INA2128U/1K input protection remains fully active even when power supplies are disconnected or turned off. Each input withstands ±40 V continuously without damage, limiting fault current to 1.5–5 mA via internal protection circuitry. This behavior is verified in the absolute maximum ratings table and confirmed in Section 6.2.8 of the INA2128U/1K datasheet. It enables safe hot-plug operation in modular I/O systems where sensor cables may be connected before power-up.

Can INA2128U/1K operate from a single 5-V supply, and what are the output swing limitations?

Yes, the INA2128U/1K operates from a single 5-V supply (V+ = 5 V, V– = 0 V), with specified performance from 4.5 V to 36 V. Output swing is limited to approximately (V+) – 1.4 V and (V–) + 1.4 V - i.e., ~0.6 V to ~3.6 V with 5-V supply. This 3-V span supports 12-bit resolution into a 3.3-V ADC. The INA2128U/1K maintains 120 dB CMR and 1.3 MHz bandwidth under these conditions, as validated in the recommended operating conditions table.

What is the channel-to-channel crosstalk specification for INA2128U/1K, and how is it minimized in layout?

The INA2128U/1K exhibits <–120 dB crosstalk at DC and low frequencies, rising to –80 dB at 100 kHz (Figure 5-11). Layout minimization requires separating IN1/OUT1 and IN2/OUT2 traces, using grounded guard rings around each channel's inputs, and routing differential pairs adjacently to convert coupled noise into common-mode signals rejected by the IA. The INA2128U/1K's independent bias circuitry ensures no shared current paths contribute to crosstalk - a key differentiator from monolithic dual op-amps.