Texas Instruments INA331AIDGKT

Overview

INA331AIDGKT from Texas Instruments is a rail-to-rail output, low-power CMOS instrumentation amplifier optimized for single-supply operation (2.7V to 5.5V), delivering 2.0MHz bandwidth, 5V/µs slew rate, and ±250µV max input offset voltage. It features internal gain of 5V/V (0.02% accuracy), shutdown current of 0.01µA, and operates across –55°C to +125°C - ideal for battery-powered sensor signal conditioning in industrial and medical systems.

For engineers reviewing the INA331AIDGKT datasheet, INA331AIDGKT pinout, INA331AIDGKT application, or INA331AIDGKT equivalent, key selection criteria include its rail-to-rail output swing (within 25mV of rails at 10kΩ load), ultra-low bias current (0.5pA), high CMRR (94dB DC), and MSOP-8 package compatibility with space-constrained PCB layouts.

Technical Context

The INA331AIDGKT implements a modified two-op-amp instrumentation architecture with an integrated third gain stage, enabling precise differential-to-single-ended conversion while maintaining high common-mode rejection up to 45kHz. Its internal 5V/V gain is fixed but extendable via external resistors using G = 5 + (5R₂/R₁).

It supports true single-supply operation with input common-mode range extending to within 0.35V of V– and 1.2V below V+, and output swing to within 25mV of either rail at G ≥ 10. Shutdown mode activates when the Shutdown pin drops below 0.8V (at 5V supply), reducing quiescent current to 0.01µA with microsecond wake-up.

Key Specifications

Pinout & Package

INA331AIDGKT is housed in an 8-pin MSOP (DGK) package - 3.0mm × 3.0mm footprint, 0.65mm pitch, 1.1mm height - suitable for high-density PCBs in handheld and IoT edge devices.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA333AIDGKT and AD8421ARMZ, the INA331AIDGKT offers the best balance of low power, precision, and compact size for cost-sensitive industrial and medical sensor nodes - neither alternative matches its 415µA IQ + 94dB CMRR + 3.0×3.0mm footprint combination.

Availability

INA331AIDGKT is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological signal acquisition, and A/D converter signal conditioning requiring stable component supply across automotive, medical, and energy metering programs.

Supply support for INA331AIDGKT 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 INA331AIDGKT belongs to TI's precision instrumentation amplifier product line, designed specifically for low-power, single-supply sensor signal conditioning in harsh industrial and portable medical environments.

FAQ

What is the maximum operating supply voltage for the INA331AIDGKT?

The INA331AIDGKT has an absolute maximum supply voltage of 7.5V (V+ to V–), but its specified operating range is +2.7V to +5.5V. Operating outside this range may cause parametric degradation or permanent damage. For reliable performance in battery-powered designs, use 3.3V or 5V supplies aligned with the device's tested specifications - the INA331AIDGKT delivers full accuracy and rail-to-rail output only within this window.

How does the INA331AIDGKT achieve rail-to-rail output swing?

The INA331AIDGKT uses a class AB output stage with common-source transistors to enable rail-to-rail output for gains ≥10. At G=5, output swing is limited to within 50mV of the rails; at G≥10 and RL≥10kΩ, it reaches within 25mV. This behavior is confirmed in the Electrical Characteristics table and Typical Characteristics curves - the INA331AIDGKT's output stage is explicitly optimized for high-fidelity signal delivery into ADCs and other downstream stages without external level-shifting circuitry.

Can the INA331AIDGKT be used with a single 3.3V supply?

Yes - the INA331AIDGKT is fully specified for single-supply operation from +2.7V to +5.5V, including 3.3V. Its input common-mode range extends from 0.35V to (V+ – 1.2V), and output swings to within 25mV of both rails at G≥10. With proper REF pin biasing (e.g., 1.65V), the INA331AIDGKT maintains full functionality in 3.3V systems such as IoT sensor nodes and portable diagnostics - no dual supplies or charge pumps are needed.

What is the purpose of the RG pin on the INA331AIDGKT?

The RG pin on the INA331AIDGKT sets gain for values >5V/V using the equation G = 5 + (5R₂/R₁). With RG left open, the device operates at its internal fixed gain of 5V/V. External resistors connected between RG, V+, and V– allow programmable gain up to 1000V/V. This flexibility makes the INA331AIDGKT adaptable across multiple sensor types - for example, configuring G=100 for low-output thermocouples or G=5 for high-output bridge sensors - all within the same MSOP-8 footprint.

Does the INA331AIDGKT require external input protection diodes?

No - the INA331AIDGKT integrates ESD protection diodes on VIN+ and VIN– pins that clamp input voltages exceeding the supply rails by >500mV. As long as input current is limited to ≤10mA (e.g., via series resistors), the device tolerates transient overvoltages without external components. This built-in protection simplifies front-end design for industrial field sensors and medical leads - the INA331AIDGKT's robust input structure eliminates the need for discrete TVS or Schottky clamps in most applications.