The input protection diodes are useful in certain party-line

systems which may have multiple V+ power supplies and, in

which case, may be operated with some of the V+ supplies

turned off. In such a system, if a supply is turned off and al-

lowed to go to ground, the equivalent input circuit connected

to that supply would be as follows:

This would be a problem in specific systems which might

possibly have the transmission lines biased to some poten-

tial greater than 1.4V. Since this is not a widespread applica-

tion problem, both the “A” and standard devices will be avail-

able. The ratings and characteristic specifications of the “A”

devices are the same as those of the standard devices.

Standard Devices

DS009446-8

“A” Devices

DS009446-9

Standard Devices

DS009446-10

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