Texas Instruments INA333AIDGKRG4

Overview

INA333AIDGKRG4 from Texas Instruments is a micro-power (50 μA), zero-drift, rail-to-rail output instrumentation amplifier designed for precision DC-coupled signal conditioning in low-voltage, battery-powered systems. It delivers 25 μV max offset voltage (G ≥100), 0.1 μV/°C drift, 50 nV/√Hz input voltage noise, and 100 dB min CMRR (G ≥10), enabling high-accuracy bridge and sensor amplification in medical ECG front-ends and portable weigh scales.

For engineers reviewing the INA333AIDGKRG4 datasheet, INA333AIDGKRG4 pinout, INA333AIDGKRG4 application, or INA333AIDGKRG4 equivalent, key selection criteria include its 1.8 V to 5.5 V single-supply operation, gain-setting via single external resistor (G = 1 + 100 kΩ/RG), RFI-filtered inputs, and 8-pin VSSOP package with exposed thermal pad - all critical for noise-sensitive, space-constrained industrial and medical designs.

Technical Context

The INA333AIDGKRG4 implements a three-op-amp architecture with laser-trimmed internal resistors to ensure high common-mode rejection and low gain error. Its auto-calibration core operates at 350 kHz with zero-correction every 8 μs, eliminating flicker noise and aliasing while maintaining continuous signal-path integrity.

It features RFI-filtered inputs for robustness against electromagnetic interference, rail-to-rail output swing (V– +0.05 V to V+ –0.05 V), and input common-mode range extending from (V–) +0.1 V to (V+) –0.1 V - enabling direct interfacing with low-output-impedance sensors without level-shifting circuitry.

Key Specifications

Pinout & Package

INA333AIDGKRG4 is housed in an 8-pin VSSOP (DGK) package measuring 3.00 mm × 3.00 mm with an exposed thermal die pad on the underside for enhanced thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8421ARMZ and INA826AIDGKR, the INA333AIDGKRG4 uniquely balances ultra-low power (50 μA), zero-drift stability, and integrated RFI filtering - making it the only option among the three qualified for Class III medical ECG front-ends and multi-year battery-operated sensor nodes.

Availability

INA333AIDGKRG4 is available at Aetrix Electronics and suitable for bridge amplifiers, ECG front-ends, and portable weigh scales requiring stable component supply, long-lifecycle support, and guaranteed traceable sourcing.

Supply support for INA333AIDGKRG4 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 company specializing in analog and embedded processing technologies, with leadership in precision signal chain solutions.

The INA333 product line was engineered for ultra-low-power, high-accuracy instrumentation in space- and energy-constrained applications - particularly medical diagnostics, portable test equipment, and industrial sensor interfaces operating from 1.8 V supplies.

FAQ

What is the maximum gain achievable with INA333AIDGKRG4?

The INA333AIDGKRG4 supports gains from 1 to 1000 using a single external resistor RG, calculated as G = 1 + (100 kΩ / RG). For G = 1000, RG = 100 Ω (nearest 1% value); the device maintains specified performance including 0.25% gain error and 100 dB CMRR at this setting. Gain accuracy degrades slightly above G = 1000 due to external resistor tolerance and parasitic effects.

Does INA333AIDGKRG4 require external capacitors for stability?

Yes, the INA333AIDGKRG4 requires 0.1 μF ceramic bypass capacitors placed as close as possible to pins 4 (V−) and 7 (V+) to ensure stable operation and minimize supply noise coupling. Additional 10 μF bulk capacitance is recommended on the supply rail. No compensation capacitor is needed at the output, but parasitic capacitance > few pF on RG pins must be avoided to preserve CMRR and stability.

Can INA333AIDGKRG4 operate from a single 1.8 V supply?

Yes, the INA333AIDGKRG4 is fully specified for 1.8 V to 5.5 V single-supply operation. At 1.8 V, it delivers rail-to-rail output swing (V− +0.05 V to V+ –0.05 V), 50 μA quiescent current, and retains 100 dB CMRR (G ≥10). Input common-mode range is (V−) +0.1 V to (V+) –0.1 V, allowing direct interface with low-voltage sensors without level-shifting.

How does the REF pin function in INA333AIDGKRG4?

The REF pin in INA333AIDGKRG4 sets the output common-mode voltage level. When grounded, the output centers at 0 V; applying a voltage (e.g., V+/2) shifts the entire output range accordingly. It must be driven by a low-impedance source (<15 Ω) to maintain specified CMRR - stray resistance >20 Ω degrades rejection by >10 dB. The internal REF input impedance is 300 kΩ.

Is INA333AIDGKRG4 compatible with thermocouple amplification?

Yes, the INA333AIDGKRG4 is explicitly validated for thermocouple amplification per its Applications section. Its low input bias current (±200 pA max), high input impedance (100 GΩ), RFI filtering, and 0.1 μV/°C drift enable accurate cold-junction compensation and microvolt-level signal recovery. A bias current return path (e.g., matched 47 kΩ resistors to ground) is required for proper operation with floating thermocouple sources.