ISO6442FDFPR datasheet(26/56 Pages) TI2

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8 Detailed Description

8.1 Overview

The ISO644x family of devices have 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 ISO644x devices also incorporate advanced circuit

techniques to maximize the CMTI performance and minimize the radiated emissions due to the high frequency

carrier and IO buffer switching.

8.2 Functional Block Diagram

INx

Oscillator

OOK

Modulation

Transmitter

Emissions

Reduction

Circuit

TX Signal

Conditioning

Envelope

Detection

RX Signal

Conditioning

Receiver

ENx

OUTx

Isolation

Barrier

Figure 8-1. Conceptual Block Diagram of an OOK Based Digital Isolator

Figure 8-2 shows a conceptual detail of how the ON-OFF keying scheme works.

TX IN

RX OUT

Carrier signal through

isolation barrier

Figure 8-2. On-Off Keying (OOK) Based Modulation Scheme

ISO6440, ISO6441, ISO6442

SLLSG01B – SEPTEMBER 2024 – REVISED NOVEMBER 2025

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ISO6442FDFPR Datasheet(PDF) 26 Page - Texas Instruments