INA821 datasheet(19/51 Pages) TI2

19 / 51 page

8 Detailed Description

8.1 Overview

The INA819 is a monolithic precision instrumentation amplifier that incorporates a current-feedback input stage

and a four-resistor difference amplifier output stage. The functional block diagram in the next section shows how

the differential input voltage is buffered by Q1 and Q2 and is forced across RG, which causes a signal current to

flow through RG, R1, and R2. The output difference amplifier, A3, removes the common-mode component of the

input signal and refers the output signal to the REF pin. The VBE and voltage drop across R1 and R2 produce

output voltages on A1 and A2 that are approximately 0.8 V lower than the input voltages.

Each input is protected by two field-effect transistors (FETs) that provide a low series resistance under

normal signal conditions, and preserve excellent noise performance. When excessive voltage is applied, these

transistors limit input current to approximately 8 mA.

8.2 Functional Block Diagram

25 k

+VS

–VS

+VS

–VS

+VS

–VS

Super-

NPN

Super-

NPN

(External)

+VS

–VS

Overvoltage

Protection

Overvoltage

Protection

–IN

+IN

REF

OUT

+VS

IB Cancellation

25 k

40 k

–VS

+VS

www.ti.com

INA819

SBOS959D – DECEMBER 2018 – REVISED APRIL 2022

Submit Document Feedback

Product Folder Links: INA819

INA821 Scheda tecnica(PDF) 19 Page - Texas Instruments

INA821 Scheda tecnica(HTML) 19 Page - Texas Instruments

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51

Scheda tecnica Scarica

Link URL