TX

Reinforced

Isolation

Barrier

Bandgap

Reference

OUTP

OUTN

GND1

IN

VCAP

VDD1

ISO224

RX

Data

CLK

VDD2

GND2

VDD1

Detection

Voltage Regulator

(LDO)

Clamp

û

Modulator

Bandgap

Reference

RX

TX

Oscillator

17

ISO224

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SBAS738A – JUNE 2018 – REVISED OCTOBER 2018

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8 Detailed Description

8.1 Overview

The ISO224 is a precision, isolated amplifier with a high input impedance and wide input voltage range suitable

for wide range of industrial applications. The input stage of the device drives a delta-sigma (ΔΣ) modulator. The

modulator uses the internal voltage reference and clock generator to convert the analog input signal to a digital

bitstream. The drivers (called TX in the Functional Block Diagram section) transfer the output of the modulator

across the isolation barrier that separates the high-side and low-side voltage domains. The received bitstream

and clock are synchronized and processed by a digital-to-analog conversion stage on the low-side and presented

as a differential analog output.

The SiO2-based, double-capacitive isolation barrier supports a high level of magnetic field immunity, as described

in ISO72x Digital Isolator Magnetic-Field Immunity. The digital modulation used in the ISO224 and the isolation

barrier characteristics result in high reliability and high common-mode transient immunity.

8.2 Functional Block Diagram