The STCAP pin acts like a delay circuit. Due to

the large capacitor (470

µF), the STCAP pin allows

the battery voltage to decay slowly giving the mi-

croprocessor time to store data. Also, during short

low voltage or negative voltage conditions, the

STCAP pin protects the 5V st-by output from

dropping below the RESET and LVW trip points

The four outputs are expected to follow the bat-

tery voltage down to 7V. At 7V typical the LVW

tells the microprocessor to stop operation and

save operating data Below 7V the outputs are ex-

pected to stay alive and ready for a return of bat-

tery.

The L4948 has a st-by mode to keep the micro-

processor and memories allive during an ignition

off conditions. The ON/OFF input pin in controlled

by the microprocessor. An high on the ON/OFF

pin places the part in normal mode. A low on the

Notes and Information

The following information is for clarification, not for specification definition.

Please use the information in this way.

L4948

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