8 Detailed Description

8.1 Overview

INA350 is a selectable gain instrumentation amplifier mainly targeted 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. It incorporates a three op amp INA architecture integrating three operational

amplifiers and seven precision matched integrated resistors. It is mainly targeted for use in 10-bit to 14-bit

systems, 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 INA350 is that it does not need any external resistors to set the gain. Often these

external resistors warrant tighter tolerance and need to be routed carefully which adds to the system complexity

and cost. INA350 is offered in four gain options across two variants. INA350ABS has two gain options of 10 and

20. INA350CDS 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 it is designed with an internal pull up to

default to the same configuration as GS tied logic high.

The INA350 is developed for industrial applications in factory automation and appliances sector where pressure

sensing and temperature sensing are done using bridge-type sensor networks and load cells. It can also be used

in tight spaces in medical applications such as patient monitoring, sleep diagnostics, electronic hospital beds,

blood glucose monitoring, and so forth for voltage sensing and differential to single-ended conversion. INA350

can enable these applications to reduce their 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.

8.2 Functional Block Diagram

+

–

+

–

+

–

60 k

60 k

60 k

60 k

REF

V+

OUT

V

IN

+IN

90 k

/ 145 k

90 k

/ 145 k

GS

SHDN

_____

Note: 90 kΩ for INA350ABS and 145 kΩ for INA350CDS

Simplified Internal Schematic

www.ti.com

INA350

SBOSAA0B – NOVEMBER 2021 – REVISED APRIL 2022

Copyright © 2022 Texas Instruments Incorporated

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Product Folder Links: INA350