L4901 datasheet(5/10 Pages) STMICROELECTRONICS

5 / 10 page

tion.

This output may thereforebe usedto supply circuits

continuously, such as volatile RAMs, allowing the

use of a back-up battery. The V01 regulator also

features low consumption (0.6 mA typ.) to minimize

battery drain in applicationswhere the V1 regulator

is permanently connected to a battery supply.

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.

APPLICATIONS SUGGESTIONS

Figure 2 shows an application circuit for a

µP

system typically used in trip computers or in car

radios with programmable tuning.

Reg. 1 is permanently connected to a battery and

supplies a CMOS time-of-day clock and a CMOS

microcomputer chip with volatile memory.

Reg. 2 may be switched OFF when the system is

Figure 2

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

L4901A

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L4901 bảng dữ liệu(PDF) 5 Page - STMicroelectronics