7.4 Device Functional Modes

Table 7-2 lists the functional modes for the ISO774x devices.

Table 7-2. Function Table

VCCI

VCCO

INPUT

(INx)(2)

OUTPUT

ENABLE

(ENx)

OUTPUT

(OUTx)

COMMENTS

PU

PU

H

H or open

H

Normal Operation:

A channel output assumes the logic state of the input.

L

H or open

L

Open

H or open

Default

Default mode: When INx is open, the corresponding channel output

goes to the default logic state. Default is High for ISO774x and Low

for ISO774x with F suffix.

X

PU

X

L

Z

A low value of output enable causes the outputs to be high-

impedance.

PD

PU

X

H or open

Default

Default mode: When VCCI is unpowered, a channel output assumes

the logic state based on the selected default option. Default is High

for ISO774x and Low for ISO774x with F suffix.

When VCCI transitions from unpowered to powered-up, a channel

output assumes the logic state of the input.

When VCCI transitions from powered-up to unpowered, channel

output assumes the selected default state.

X

PD

X

X

Undetermined

When VCCO is unpowered, a channel output is undetermined(1).

When VCCO transitions from unpowered to powered-up, a channel

output assumes the logic state of the input.

(1)

The outputs are in undetermined state when 1.7 V < VCCI, VCCO < 2.25 V.

(2)

A strongly driven input signal can weakly power the floating VCC through an internal protection diode and cause undetermined output.

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ISO7740, ISO7741, ISO7742

SLLSEP4J – MARCH 2016 – REVISED OCTOBER 2024

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