TX IN

RX OUT

Carrier signal through

isolation barrier

TX IN

Oscillator

OOK

Modulation

Transmitter

Emissions

Reduction

Techniques

TX Signal

Conditioning

Envelope

Detection

RX Signal

Conditioning

Receiver

RX OUT

Capacitive

Isolation

Barrier

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ISO7760, ISO7761

ISO7762, ISO7763

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SLLSER1A – AUGUST 2017 – REVISED AUGUST 2017

Product Folder Links: ISO7760 ISO7761 ISO7762 ISO7763

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8 Detailed Description

8.1 Overview

The ISO776x family of devices uses an ON-OFF keying (OOK) modulation scheme to transmit the digital data

across a silicon-dioxide based isolation barrier. The transmitter sends a high-frequency carrier across the barrier

to represent one digital state and sends no signal to represent the other digital state. The receiver demodulates

the signal after advanced signal conditioning and produces the output through a buffer stage. The ISO776x

family of devices also incorporates advanced circuit techniques to maximize the CMTI performance and minimize

the radiated emissions because of the high-frequency carrier and IO buffer switching. The conceptual block

diagram of a digital capacitive isolator, Figure 15, shows a functional block diagram of a typical channel.

Figure 16 shows a conceptual detail of how the ON-OFF keying scheme works.

8.2 Functional Block Diagram

Figure 15. Conceptual Block Diagram of a Digital Capacitive Isolator

Figure 16. ON-OFF Keying (OOK) Based Modulation Scheme