Texas Instruments INA322EA/2K5

Overview

INA322EA/2K5 from Texas Instruments is a micropower, single-supply, CMOS instrumentation amplifier in MSOP-8 package, delivering 500kHz bandwidth at G = 5V/V, 40µA/channel quiescent current, and rail-to-rail output swing within 20mV of rails (G ≥ 10). It serves as a precision front-end for low-power sensor signal conditioning in battery-operated industrial and medical systems.

For engineers reviewing the INA322EA/2K5 datasheet, INA322EA/2K5 pinout, INA322EA/2K5 application, or INA322EA/2K5 equivalent, key selection considerations include its programmable gain architecture (G = 5 + 5(R₂/R₁)), –55°C to +125°C operating range, shutdown current <1µA, 10pA input bias current, and compatibility with single-supply bridge, RTD, and ECG sensing topologies.

Technical Context

The INA322EA/2K5 implements a modified two-op-amp instrumentation amplifier topology with an integrated third gain stage, enabling high common-mode rejection (73dB at DC, >60dB up to 3kHz) while maintaining low power. Its CMOS input stage provides 10¹³Ω input impedance and 10pA bias current, supporting high-impedance sensors without loading.

Gain is externally set via resistors R₁ and R₂ on pins 1, 5, and 6, with internal 5V/V base gain yielding total gain G = 5 + 5(R₂/R₁), covering 5–1000V/V. The reference pin (pin 4) defines output zero level and directly affects common-mode input range, requiring low-impedance connection to preserve CMRR.

Key Specifications

Pinout & Package

INA322EA/2K5 is housed in an 8-pin MSOP (VSSOP-DGK) package, 3.0mm × 3.0mm × 1.1mm, with exposed thermal pad. Pin 1 is marked by a dot or beveled corner; the package is RoHS-compliant and moisture-sensitivity level 2 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA333AIDR and AD8226ARMZ, the INA322EA/2K5 uniquely balances micropower operation (40µA), hardware shutdown (<1µA), wide temperature range (–55°C to +125°C), and fully programmable gain - making it optimal for multiplexed, battery-powered, high-reliability sensor nodes where flexibility and robustness are co-prioritized.

Availability

INA322EA/2K5 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, portable physiological monitors, and A/D converter signal conditioning requiring stable component supply across automotive, energy metering, and medical OEM programs.

Supply support for INA322EA/2K5 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 INA322 family was designed specifically for low-cost, micropower instrumentation in harsh-environment sensor interfaces - targeting applications where rail-to-rail output, programmable gain, and extended temperature operation are critical.

FAQ

What is the maximum gain achievable with INA322EA/2K5, and how is it configured?

The INA322EA/2K5 supports gains from 5V/V to 1000V/V using external resistors R₁ and R₂ connected to pins 1, 5, and 6. The gain equation is G = 5 + 5(R₂/R₁). For example, setting R₂ = 90kΩ and R₁ = 10kΩ yields G = 50V/V. Maximum gain is limited by stability and bandwidth trade-offs - at G = 1000, bandwidth drops to ~5kHz. The INA322EA/2K5 datasheet provides resistor tables and layout guidance for stable high-gain configurations.

Does INA322EA/2K5 support true rail-to-rail output swing, and under what conditions?

Yes, the INA322EA/2K5 delivers rail-to-rail output swing - within 20mV of V+ and V– - but only when gain is ≥10V/V and load resistance is ≥25kΩ. At G = 5, the output does not reach the positive rail due to internal stage headroom limitations. Performance degrades with heavier loads: at 10kΩ and 125°C, swing reduces to ~100mV from rails. The INA322EA/2K5's output stage is optimized for high-Z ADC inputs, not low-impedance drivers.

How does the shutdown feature of INA322EA/2K5 operate, and what is its recovery time?

The INA322EA/2K5 enters shutdown mode when the Shutdown pin (pin 8) is pulled below 0.8V (at V+ = 5V); quiescent current drops to <1µA. Recovery to full operation occurs in microseconds - typically <2µs - with no external reset required. During shutdown, the output assumes high-impedance state, enabling safe multiplexing of multiple INA322EA/2K5 channels onto a shared ADC input. The INA322EA/2K5 shutdown threshold varies slightly with supply voltage, as shown in the "Shutdown Voltage vs Supply Voltage" curve.

Can INA322EA/2K5 be used with single-ended sensors or only differential sources?

The INA322EA/2K5 is a true instrumentation amplifier requiring differential input signals (VIN+ and VIN–) for common-mode rejection. It cannot directly amplify single-ended sources without external circuitry. However, single-ended transducers (e.g., thermistors, RTDs) can be used by configuring them in a resistive bridge with a second matched element - the INA322EA/2K5 then amplifies the bridge's differential output. Direct single-ended use would bypass CMRR and degrade noise immunity.

What is the recommended decoupling strategy for INA322EA/2K5 in noise-sensitive applications?

For optimal performance, place a 0.1µF X7R ceramic capacitor between V+ (pin 6) and V– (pin 5), located ≤2mm from the INA322EA/2K5 package. Add a second 1µF tantalum or ceramic capacitor nearby for bulk filtering. Avoid shared traces: each INA322EA/2K5 should have dedicated supply routing and local decoupling. The REF pin (pin 4) also requires low-impedance grounding - route it directly to a quiet ground plane with minimal trace length to preserve CMRR, as specified in the INA322EA/2K5 application circuits.