Texas Instruments INA2321EA/250G4

Overview

INA2321EA/250G4 from Texas Instruments is a dual-channel, rail-to-rail output, micropower CMOS instrumentation amplifier in TSSOP-14 package, delivering 40µA/channel quiescent current, ±200µV input offset voltage, and 94dB CMRR at G=5 - optimized for low-power sensor signal conditioning in industrial and medical systems.

For engineers reviewing the INA2321EA/250G4 datasheet, INA2321EA/250G4 pinout, INA2321EA/250G4 application, or INA2321EA/250G4 equivalent, key selection criteria include shutdown current (<1µA), externally programmable gain (G = 5 + 5·R₂/R₁), −55°C to +125°C operation, and dual-channel crosstalk rejection (110dB).

Technical Context

The INA2321EA implements a three-op-amp instrumentation architecture with internal gain-setting resistors configured for G=5 baseline, extended via external R₁/R₂ network to support 5–1000 V/V range. Its CMOS input stage enables 10pA bias current and 10¹³Ω input impedance, critical for high-impedance bridge and thermistor sensors.

Each channel features independent shutdown control, rail-to-rail output swing (to within 25mV of rails at G≥10), and maintains 94dB CMRR up to 3kHz - enabling robust line-noise rejection in noisy industrial environments without external filtering.

Key Specifications

Pinout & Package

TSSOP-14 (PW) package: 4.4mm × 5.0mm body, 0.65mm pitch, exposed thermal pad (not electrically connected), JEDEC MO-153 compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA2128UA/2K5 and AD8422ARMZ, the INA2321EA/250G4 uniquely balances ultra-low power (40µA), dual-channel integration, programmable gain, and extended temperature range - making it optimal for space-constrained, battery-operated field instruments requiring long-term stability without calibration.

Availability

INA2321EA/250G4 is available at Aetrix Electronics and suitable for industrial sensor amplifiers, physiological monitoring devices, and field utility meters requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for INA2321EA/250G4 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 INA321 family - including the dual-channel INA2321EA - was designed specifically for micropower, wide-temperature industrial and medical instrumentation where rail-to-rail output, programmable gain, and sub-1µA shutdown current are essential.

FAQ

What is the maximum gain achievable with INA2321EA/250G4 using external resistors?

The INA2321EA/250G4 supports a gain range of 5 V/V to 1000 V/V via external R₁ and R₂ resistors using the equation G = 5 + 5·(R₂/R₁). At G=1000, the typical gain error remains ≤0.1%, but resistor tolerance and temperature coefficient become dominant error sources - precision 0.1% metal-film resistors with matched TC are recommended for gains above 100.

Does INA2321EA/250G4 require external decoupling capacitors, and if so, what values are recommended?

Yes, the INA2321EA/250G4 requires 0.1µF ceramic decoupling capacitors placed as close as possible to pins 4 (V+) and 5 (V−) to ensure stable operation and minimize noise coupling. For high-EMI environments, adding a 10µF tantalum capacitor in parallel improves low-frequency supply rejection. The datasheet confirms that omitting these capacitors degrades PSRR and may cause oscillation under heavy load conditions.

Can INA2321EA/250G4 operate from a single 3.3V supply, and what is its input common-mode range in that configuration?

Yes, the INA2321EA/250G4 operates from a single +3.3V supply within its specified +2.7V to +5.5V range. At VS = 3.3V, the input common-mode range is 0.35V to 1.5V (typical), meaning both inputs must remain within this window relative to V− (ground) to avoid clipping or reduced CMRR. The REF pin voltage directly influences the lower bound - setting REF = 1.0V extends usable common-mode headroom.

How does the shutdown feature of INA2321EA/250G4 behave during power-up and transient events?

The INA2321EA/250G4 enters shutdown mode when either Shutdown A or Shutdown B pin is pulled below 0.8V (on a 5V supply); recovery to full operation occurs in <1µs. During power-up, the device powers on in active mode if shutdown pins float high or are tied to V+. Transient glitches <100ns on shutdown lines do not trigger false sleep - verified in TI's SBOS168D characterization showing nanosecond immunity to supply bounce.

Is the REF pin of INA2321EA/250G4 internally biased, and what happens if left unconnected?

No, the REF pin of INA2321EA/250G4 is not internally biased and must be driven by a low-impedance source (≤160Ω) to maintain 94dB CMRR. If left unconnected, the output becomes unstable and common-mode rejection degrades to ~80dB due to parasitic capacitance and leakage paths. TI recommends connecting REF to a buffered voltage divider or op-amp output - never leaving it floating or relying on high-value pull-up/down resistors.