INA351 datasheet(19/46 Pages) TI

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7 Detailed Description

7.1 Overview

The INA351 is a selectable gain instrumentation amplifier with integrated reference buffer designed to provide

an integrated, small size, cost-effective solution for applications employing general purpose INAs or discrete

implementation of INAs using commodity amplifiers and resistors. The device incorporates a three op amp

INA architecture integrating three operational amplifiers and seven precision matched integrated resistors. The

INA351 is designed for 10-bit to 14-bit systems without any additional effort, but calibrating offset and gain error

at a system level can further improve system resolution and accuracy, enabling use in precision applications.

One of the key features of the INA351 is that the device does not need any external resistors to set the gain.

Often these external resistors require tighter tolerance and careful routing, which adds to system complexity and

cost. The INA351 is offered in four gain options across two variants. The INA351ABS has two gain options of

10 and 20. The INA351CDS has two other gain options of 30 and 50. Gains can be selected by connecting the

GS pin to logic high or logic low. Note that the GS pin can be left floating as well, as the pin is designed with an

internal pull up to default to the same configuration as GS tied logic high.

The INA351 is designed for industrial applications leveraging pressure and temperature sensing via bridge-type

sensor networks and load cells. The device can also be used in space-constrained applications such as patient

monitoring, sleep diagnostics, electronic hospital beds, and blood glucose monitoring for voltage sensing and

differential to single-ended conversion. The INA351 can enable these applications to reduce the overall size

through the use of tiny packages, including a 2-mm × 1.5-mm X2QFN package and a 2-mm × 2-mm WSON

package.

7.2 Functional Block Diagram

–

60 k

REF

V+

OUT

+IN

90 k

/ 145 k

90 k

/ 145 k

SHDN

_____

Note: 90 kΩ for INA351ABS and 145 kΩ for INA351CDS

Simplified Internal Schematic

www.ti.com

INA351

SBOSAD5D – DECEMBER 2022 – REVISED NOVEMBER 2024

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INA351 Datasheet(PDF) 19 Page - Texas Instruments