This output may thereforebe usedto supply circuits

continuously, such as volatile RAMs, allowing the

use of a back-up battery.

circuits which may be powered down when the

system is inactive, or that must be powered down

to prevent uncorrect operation for supply voltages

below the minimum value.

The reset output can be usedas a ”POWER DOWN

INTERRUPT”, permitting RAM access only in cor-

rect power conditions, or as a ”BACK-UP ENABLE”

to transfer data into in a NV SHADOW MEMORY

when the supply is interrupted.

The disable function can be used for remote on/off

APPLICATION SUGGESTIONS

Figure 2 illustrate how the L4902A’s disable input

may be used in a CMOS

µComputer application.

nently a CMOS time of day clock and a CMOS

supplying non-essential circuits, is turned OFF un-

der control of a

µP unit.

Figure 2

Figure 3 : P.C. Board Component Layout of Figure 2

L4902A

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