Texas Instruments INA821IDRGT

Overview

INA821IDRGT from Texas Instruments is a precision instrumentation amplifier with 35-µV maximum input offset voltage, 7-nV/√Hz input voltage noise, and 4.7-MHz bandwidth at G = 1. It features ±40-V input overvoltage protection, 112-dB minimum CMRR at G = 10, and operates from ±2.25 V to ±18 V dual supplies or 4.5 V to 36 V single supply - used in ECG front-ends and industrial process analytics for high-fidelity differential signal conditioning.

For engineers reviewing the INA821IDRGT datasheet, INA821IDRGT pinout, INA821IDRGT application, or INA821IDRGT equivalent, this page delivers verified specifications, package mapping (WSON-8), gain-setting resistor interface (RG pins 2 & 3), thermal pad connection guidance, and two validated alternative parts with documented functional trade-offs.

Technical Context

The INA821IDRGT uses super-beta input transistors to achieve low input bias current (0.15–0.5 nA) and ultra-low input offset drift (0.1–0.4 µV/°C). Its three-op-amp architecture enables independent gain setting via external resistor RG between pins 2 and 3, supporting gains from 1 to 10,000 using the equation G = 1 + 49.4 kΩ/RG.

It integrates input-stage overvoltage protection up to ±40 V relative to supplies and maintains stability with 1-nF capacitive loads. The reference input (REF, pin 6) has 10-kΩ input impedance and unity gain to output, enabling precise level-shifting of the output common-mode voltage.

Key Specifications

Pinout & Package

The INA821IDRGT is housed in an 8-pin WSON package (3.0 mm × 3.0 mm, DRG suffix), with exposed thermal pad internally connected to –VS. External connection of the thermal pad to –VS improves thermal resistance (R_θJB = 28.6°C/W) and power dissipation capability.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA819IDGKT and INA828IDRGT, the INA821IDRGT delivers the lowest input-referred offset voltage (35 µV max) and best input offset drift (0.4 µV/°C max), making it the preferred choice for applications demanding highest DC precision and low-frequency noise performance.

Availability

INA821IDRGT is available at Aetrix Electronics and suitable for analog input modules, electrocardiogram (ECG) systems, and flow transmitters requiring stable component supply, long-lifecycle support, and guaranteed traceability for medical and industrial certifications.

Supply support for INA821IDRGT 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 components.

The INA821IDRGT belongs to TI's high-precision instrumentation amplifier product line, designed specifically for low-drift, low-noise differential signal acquisition in medical diagnostics, industrial process control, and test equipment.

FAQ

What is the gain-setting resistor configuration for the INA821IDRGT?

The INA821IDRGT uses an external resistor (RG) placed between pins 2 and 3 to set gain according to G = 1 + 49.4 kΩ/RG. For example, a 49.4-kΩ resistor yields G = 2; a 494-Ω resistor yields G = 101. The INA821IDRGT does not require internal trimming or digital configuration - gain is purely analog and resistor-defined.

Does the INA821IDRGT require external protection diodes on its inputs?

No, the INA821IDRGT includes integrated overvoltage protection that withstands ±40 V on the ±IN pins regardless of supply voltage or state. This eliminates the need for external series resistors or clamping diodes in most industrial and medical applications, reducing BOM count and PCB area.

What is the function of the REF pin on the INA821IDRGT?

The REF pin (pin 6) on the INA821IDRGT provides a unity-gain buffered reference input that directly controls the output common-mode voltage. Driving REF with a stable voltage (e.g., mid-supply or DAC output) shifts the entire output range without affecting gain or differential accuracy - essential for interfacing with ADCs requiring specific input voltage ranges.

Can the INA821IDRGT operate from a single 5-V supply?

Yes, the INA821IDRGT supports single-supply operation from 4.5 V to 36 V. At 5 V, its output swings from ~150 mV above –VS (ground) to ~150 mV below +VS, and input common-mode range extends from (V–) + 2 V to (V+) – 2 V - enabling direct use with 3.3-V or 5-V microcontrollers and SAR ADCs without level-shifting circuitry.

How does the thermal pad on the INA821IDRGT WSON package affect performance?

The exposed thermal pad on the INA821IDRGT (DRG package) is internally connected to –VS and must be soldered to a PCB copper pour tied to –VS or system ground. Proper thermal pad connection reduces R_θJB to 28.6°C/W, lowering junction temperature by >20°C at 650 µA quiescent current - critical for maintaining 35-µV offset stability and long-term reliability in sealed enclosures.