L4902A datasheet(5/9 Pages) STMICROELECTRONICS

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This output may thereforebe usedto supply circuits

continuously, such as volatile RAMs, allowing the

use of a back-up battery.

The V02 output can supply other non essential 5 V

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

control of circuits connected to the V02 output.

APPLICATION SUGGESTIONS

Figure 2 illustrate how the L4902A’s disable input

may be used in a CMOS

µComputer application.

TheV01 regulator(low consumption)supply perma-

nently a CMOS time of day clock and a CMOS

µcomputer chip with volatile memory. V02 output,

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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L4902A Arkusz danych(PDF) 5 Page - STMicroelectronics