Texas Instruments INA351AIDSGR

Overview

INA351AIDSGR from Texas Instruments is a fixed-gain (10 V/V) instrumentation amplifier with integrated configurable reference amplifier, designed for precision low-frequency signal conditioning in space-constrained medical and industrial sensors. It delivers 86 dB minimum CMRR, 0.1% max gain error, 100 kHz bandwidth, 110 µA typical quiescent current, and operates from 1.8 V to 5.5 V supply - enabling direct interfacing with 10–14-bit delta-sigma ADCs in battery-powered ECG and wearable monitors.

For engineers reviewing the INA351AIDSGR datasheet, INA351AIDSGR pinout, INA351AIDSGR application, or INA351AIDSGR equivalent, this page provides verified technical context, package-validated pin functions, real-world application mappings, and two confirmed alternative parts with documented functional and application-level differences - all grounded in TI's SBOSAG2 production data sheet (June 2023).

Technical Context

The INA351AIDSGR integrates four op-amps and seven precision-matched thin-film resistors to achieve stable G = 10 amplification without external gain-setting components. Its dual-stage architecture separates differential amplification (first stage) from common-mode rejection and output buffering (second stage), with the reference amplifier's output internally tied to the 60 kΩ resistor node (REF) to set output common-mode voltage.

DC precision is enhanced via the configurable reference amplifier, which supports closed-loop servo calibration of sensor offset and drift - particularly effective for sub-1 Hz biomedical signals like ECG and EEG. The device maintains rail-to-rail input common-mode range across its full supply range and drives up to 1 nF capacitive loads with <10% overshoot, eliminating need for external output buffers in many portable designs.

Key Specifications

Pinout & Package

INA351AIDSGR is housed in an 8-pin WSON (DSG) package with 2 mm × 2 mm footprint and exposed thermal pad (connected to V–). The package supports high-density PCB layouts and efficient thermal dissipation in compact sensor modules.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA351AIDSGR, INA333AIDGKR offers superior DC drift performance but lacks the integrated reference amplifier for servo calibration, while AD8221ARMZ provides wider gain flexibility and higher CMRR at the cost of significantly higher power consumption - making INA351AIDSGR the optimal choice for compact, battery-operated systems requiring both precision and active DC error correction.

Availability

INA351AIDSGR is available at Aetrix Electronics and suitable for electrocardiogram monitors, pressure transmitters, and wearable fitness devices requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for INA351AIDSGR 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 for medical, industrial, and automotive markets.

The INA351A product line targets ultra-low-power, space-constrained sensor signal conditioning - specifically engineered to replace discrete instrumentation amplifier designs while delivering calibrated DC precision, robust EMI immunity, and seamless integration with delta-sigma ADCs.

FAQ

What is the function of the A_IN+, A_IN–, and A_OUT pins on the INA351AIDSGR?

The A_IN+, A_IN–, and A_OUT pins constitute the configurable reference amplifier within the INA351AIDSGR. A_IN+ accepts an external reference voltage (e.g., from a DAC or filtered sensor bias), A_IN– serves as the inverting input for servo-loop feedback, and A_OUT provides the buffered output tied internally to the 60 kΩ resistor node (REF). This architecture enables precise output common-mode control or closed-loop DC error calibration - a capability not found in standard instrumentation amplifiers.

Can the INA351AIDSGR drive a 10-bit delta-sigma ADC directly without an external buffer?

Yes, the INA351AIDSGR can directly drive 10-bit to 14-bit delta-sigma ADCs without an external buffer. Its output stage is specified to drive ≥1 nF capacitive loads with <10% overshoot and maintains 51 Ω closed-loop output impedance at 10 kHz. Combined with its 100 kHz bandwidth and rail-to-rail output swing (within 15–30 mV of rails), it meets timing and settling requirements for typical sigma-delta converters sampling at ≤10 kSPS - simplifying front-end design in portable medical devices.

What is the minimum supply voltage for the INA351AIDSGR, and how does it affect performance?

The INA351AIDSGR operates down to 1.8 V single-supply (±0.9 V dual). At this voltage, quiescent current remains at 110 µA typical, CMRR stays ≥86 dB, and gain error holds at ≤0.1%. However, output voltage swing reduces to ~1.5 Vpp (vs ~4.5 Vpp at 5.5 V), and small-signal bandwidth decreases slightly. This makes the INA351AIDSGR ideal for coin-cell–powered wearables where low-voltage operation is mandatory and dynamic range requirements are moderate.

How does the servo-loop calibration work with the INA351AIDSGR's reference amplifier?

Servo-loop calibration uses the INA351AIDSGR's reference amplifier to nullify total DC errors (offset, drift, gain error) at the main amplifier output. A low-frequency AC signal (e.g., 0.1–10 Hz square wave) is injected at the INA inputs; the resulting output DC error is sensed, integrated by the reference amplifier (configured as integrator), and fed back to A_IN–. This forces the average output to zero, effectively calibrating the entire signal path - a technique widely deployed in clinical ECG and EEG systems where baseline stability is critical.

Is the thermal pad on the DSG package of the INA351AIDSGR electrically connected, and how should it be handled on the PCB?

Yes, the exposed thermal pad on the INA351AIDSGR's DSG package is electrically connected to V– (pin 4) and must be soldered to a PCB copper pour tied to the system ground plane. This connection provides both thermal relief (reducing junction-to-board thermal resistance to 46.4°C/W) and improved noise immunity. TI recommends using 9 thermal vias (0.3 mm diameter, spaced evenly under the pad) to maximize heat transfer and minimize ground bounce in sensitive analog circuits.