RFI Filtered Inputs

RFI Filtered Inputs

50 k

RFI Filtered Inputs

RFI Filtered Inputs

50 k

150

150

150

150

INA333-Q1

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8

6

5

2

3

REF

A1

A2

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±

+

+

7

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1

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4

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A3

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INA333-Q1

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SBOS464 – OCTOBER 2019

Product Folder Links: INA333-Q1

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Copyright © 2019, Texas Instruments Incorporated

7 Detailed Description

7.1 Overview

The INA333-Q1 is a monolithic instrumentation amplifier (INA) based on the precision zero-drift INA333-Q1

(operational amplifier) core. The INA333-Q1 also integrates laser-trimmed resistors to maintain excellent

common-mode rejection and low gain error. The combination of the zero-drift amplifier core and the precision

resistors allows this device to achieve outstanding dc precision, and makes the INA333-Q1 an excellent choice

for many 3.3-V and 5-V automotive applications.

7.2 Functional Block Diagram

7.3 Feature Description

7.3.1 Operating Voltage

The INA333-Q1 operates over a power-supply range of 1.8 V to 5.5 V (±0.9 V to ±2.75 V). Supply voltages

greater than 7 V (absolute maximum) can permanently damage the device. Parameters that vary over supply

voltage or temperature are shown in the Typical Characteristics section of this data sheet.

7.3.2 Internal Offset Correction

The INA333-Q1 internal operational amplifiers use an auto-calibration technique with a time-continuous, 350-kHz

operational amplifier in the signal path. The amplifier is zero-corrected every 8 µs using a proprietary technique.

no aliasing or flicker noise.

7.3.3 Input Protection

The input pins of the INA333-Q1 are protected with internal diodes connected to the power-supply rails. These

diodes clamp and prevent the applied signal from damaging the input circuitry. If the input signal voltage exceeds

the power supplies by greater than 0.3 V, limit the input signal current to less than 10 mA to protect the internal

clamp diodes. This current limiting is generally done with a series input resistor. Some signal sources are

inherently current-limited and do not require limiting resistors.

7.4 Device Functional Modes

The INA333-Q1 has a single functional mode and is operational when the power-supply voltage is greater than

1.8 V. The recommended maximum specified power-supply voltage for the INA333-Q1 is 5.5 V.