L4948 datasheet(6/9 Pages) STMICROELECTRONICS

No de pièce	L4948

Description	QUAD VOLTAGE REGULATOR WITH INHIBIT AND RESET

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Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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FUNCTIONAL DESCRIPTION

The L4948 includes a monitoring circuit to warn

the microprocessor if a low voltage or no voltage

condition is occurring. Between 6.5V and 7.5V on

the STCAP pin, the LVW output will go low. This

tells the microprocessor to stop executing code

and save vital information. The reset output will

go low when V04 drops 0.15V below it’s typical

reading. A reset will occur between a minimum of

4.5 and a maximum of 5V on V04. When the V04

drops between 4.5 and 5V

the RESET output

goes low. It is very important that the RESET out-

put doesn’t go above 0.75V until the V04 output

has gone back above 4.75V (typical). The micro-

processor looks for a rising edge. So, any spike

will tell the microprocessor to start operating.

Once the STCAP line passes 7V (typical), the

LVW output will also return to high state.

TIMING DIAGRAM

Graphs of the Output Curves for VO1,2,3 and 4

5.0

7.8

L4948

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