Datasheet

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6 Top Layer .................................................................................................................... 6

7 Layer 2 ....................................................................................................................... 6

8 Layer 3 ....................................................................................................................... 7

9 Bottom Layer ................................................................................................................ 7

List of Tables

1 Bill of Materials .............................................................................................................. 8

Overview

The ISO71xx digital isolators have a logic input and output buffer separated by a silicon dioxide (SiO2)

insulation barrier. Used with isolated power supplies, these devices block high voltage, isolate grounds,

and prevent noise currents on a data bus or other circuits from entering the local ground and interfering

with or damaging sensitive circuitry.

A binary input signal is conditioned, translated to a balanced signal, and then differentiated by the

capacitive isolation barrier. Across the isolation barrier, a differential comparator receives the logic

transition information, then sets or resets a flip-flop and the output circuit accordingly. A periodic update

pulse is sent across the barrier to ensure the proper dc level of the output. If this dc-refresh pulse is not

received for more than 4 µs, the input is assumed to be unpowered or not being actively driven, and a

failsafe circuit drives the output to a logic-high state. For the ISO7140FCC and ISO7141FCC isolators, the

failsafe condition is the logic-low state.

CAUTION

Note that although these isolator devices provide galvanic isolation of up to

3000 Vrms, this EVM cannot be used for isolation voltage testing. It is designed

for the evaluation of device operating parameters only and may be damaged if

a voltage exceeding 5.5 V is applied anywhere in the circuit.

ISO71xx EVM User’s Guide SLLU179–March 2013

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