Table 3.2. Enable Input Truth

Part Number

EN11, 2

EN21, 2

Operation

Si8640

—

H

Outputs B1, B2, B3, B4 are enabled and follow the input state.

—

L

Outputs B1, B2, B3, B4 are disabled and in high impedance state.3

Si8641

H

X

Output A4 enabled and follows the input state.

L

X

Output A4 disabled and in high impedance state.3

X

H

Outputs B1, B2, B3 are enabled and follow the input state.

X

L

Outputs B1, B2, B3 are disabled and in high impedance state.3

Si8642

H

X

Outputs A3 and A4 are enabled and follow the input state.

L

X

Outputs A3 and A4 are disabled and in high impedance state.3

X

H

Outputs B1 and B2 are enabled and follow the input state.

X

L

Outputs B1 and B2 are disabled and in high impedance state.3

Si8645

—

—

Outputs B1, B2, B3, B4 are enabled and follow the input state.

Note:

1. Enable inputs EN1 and EN2 can be used for multiplexing, for clock sync, or other output control. EN1, EN2 logic operation is

summarized for each isolator product in Table 2. These inputs are internally pulled-up to local VDD allowing them to be connec-

ted to an external logic level (high or low) or left floating. To minimize noise coupling, do not connect circuit traces to EN1 or EN2

if they are left floating. If EN1, EN2 are unused, it is recommended they be connected to an external logic level, especially if the

Si86xx is operating in a noisy environment.

2. X = not applicable; H = Logic High; L = Logic Low.

3. When using the enable pin (EN) function, the output pin state is driven into a high-impedance state when the EN pin is disabled

(EN = 0).

Si864x Data Sheet

Device Operation

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