7.4 Device Functional Modes

Table 7-2 lists the functional modes for the ISO773x 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 ISO773x and Low for ISO773x

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

ISO773x and Low for ISO773x 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 using an internal protection diode and cause undetermined output.

7.4.1 Device I/O Schematics

985

1.5M

INx

VCCI

VCCI

VCCI

Input (Devices without F suffix)

985

1.5M

INx

VCCI

VCCI VCCI

VCCI

Input (Devices with F suffix)

Enable

1970

ENx

VCCO

VCCO

VCCO

VCCO

Output

VCCO

@20

OUTx

2M

Figure 7-3. Device I/O Schematics

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ISO7730, ISO7731

SLLSES0K – SEPTEMBER 2016 – REVISED SEPTEMBER 2025

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