Texas Instruments INA2128U

Overview

INA2128U 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, 1.3 MHz bandwidth at G=1, 120 dB min CMR, and ±40 V input protection - enabling high-accuracy measurements in industrial transmitters and medical ECG systems.

For engineers reviewing the INA2128U datasheet, INA2128U pinout, INA2128U application, or INA2128U equivalent, this page provides verified technical context, validated pin functions, real-world application mappings, and two confirmed alternative parts with documented functional trade-offs for sensor signal chain design.

Technical Context

The INA2128U implements a three-op-amp current-feedback architecture that sustains 200 kHz bandwidth even at G = 100 while consuming only 700 µA per channel. Its laser-trimmed internal 50 kΩ feedback resistors enable precise gain setting (G = 1 to 10,000) via a single external RG resistor, with gain error as low as ±0.01% at G = 1 (CSO: TID).

Input stage protection withstands ±40 V regardless of supply state, and the dual-channel layout ensures independent bias networks - eliminating inter-channel crosstalk below 100 kHz. Common-mode rejection remains ≥120 dB at G ≥ 100 and degrades only to 80 dB at G = 1 due to topology constraints.

Key Specifications

Pinout & Package

INA2128U is housed in a 16-pin SOIC (DW) package measuring 10.3 mm × 10.3 mm, with standard JEDEC MO-153 outline and 1.27 mm pitch. Pin functions are validated per TI SBOS035C Figure 4-1 (top view).

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA2128U, INA2129UA improves offset drift by 60% for extended thermal stability, while AD8226ARZ trades dual-channel integration and robust input protection for smaller size and rail-to-rail output - making INA2128U the optimal choice for dual-sensor industrial transmitters requiring field-hardened reliability.

Availability

INA2128U is available at Aetrix Electronics and suitable for pressure transmitter, temperature transmitter, and weigh scale applications requiring stable component supply across industrial OEM production cycles.

Supply support for INA2128U 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 components.

The INA2128U belongs to TI's high-accuracy instrumentation amplifier product line, engineered specifically for low-drift, low-power sensor signal conditioning in industrial process control and medical measurement equipment.

FAQ

What is the maximum gain achievable with the INA2128U?

The INA2128U supports a gain range of 1 V/V to 10,000 V/V, set by a single external resistor RG using the equation G = 1 + (50 kΩ / RG). At G = 10,000, RG = 5 Ω - requiring careful layout to minimize parasitic resistance. The INA2128U maintains 20 kHz bandwidth and 120 dB CMR at G = 1000, verified in TI SBOS035C Figure 5-1.

Does the INA2128U require external input protection diodes?

No - the INA2128U features integrated ±40 V input protection on each input pin, which remains active even when power supplies are disconnected. This eliminates the need for external clamping diodes in industrial 24 V loop-powered transmitters, as confirmed in Section 6.2.8 of the INA2128U datasheet.

Can the two channels of the INA2128U share a common reference (Ref) connection?

No - RefA (Pin 3) and RefB (Pin 11) must be independently routed. Sharing a reference introduces crosstalk and degrades CMR below 100 dB. TI explicitly states in Section 6.1 that "Ref terminals must be low-impedance connections" and warns that >8 Ω series resistance on either Ref pin reduces CMR to ~80 dB at G = 1.

What is the minimum supply voltage for the INA2128U?

The INA2128U operates with dual supplies as low as ±2.25 V (4.5 V total), maintaining full functionality including 1.3 MHz bandwidth and 120 dB CMR at G ≥ 100. At ±2.25 V, the linear input common-mode range shrinks to (V–) + 2 V to (V+) – 2 V, as shown in Figure 5-10 of the INA2128U datasheet.

How does chip site origin (CSO) affect INA2128U performance?

INA2128U is manufactured at two sites: SHE and TID. CSO: SHE guarantees 50 µV max offset and 0.5 µV/°C max drift; CSO: TID guarantees 50 µV max offset but only 0.7 nA max input bias current (vs. 5 nA for SHE). Both meet all key specs, but SHE offers tighter drift control for long-term stability-critical applications.