M41ST85Y Datasheet, PDF (1/34 Pages) STMicroelectronics – 5.0 OR 3.0V, 512 bit 64 x 8 SERIAL RTC and NVRAM SUPERVISOR

M41ST85Y
M41ST85W
5.0 or 3.0V, 512 bit (64 x 8)
Serial RTC and NVRAM Supervisor
FEATURES SUMMARY
■ 5.0 OR 3.0V OPERATING VOLTAGE
■ SERIAL INTERFACE SUPPORTS I²C BUS
(400 KHz)
■ NVRAM SUPERVISOR FOR EXTERNAL
LPSRAM
■ OPTIMIZED FOR MINIMAL
INTERCONNECT TO MCU
■ 2.5 TO 5.5V OSCILLATOR OPERATING
VOLTAGE
■ AUTOMATIC SWITCH-OVER AND
DESELECT CIRCUITRY
■ CHOICE OF POWER-FAIL DESELECT
VOLTAGES
– M41ST85Y: V_CC = 4.5 to 5.5V;
4.20V ≤ V_PFD ≤ 4.50V
– M41ST85W: V_CC = 2.7 to 3.6V;
2.55V ≤ V_PFD ≤ 2.70V
■ 1.25V REFERENCE (for PFI/PFO)
■ COUNTERS FOR TENTHS/HUNDREDTHS
OF SECONDS, SECONDS, MINUTES,
HOURS, DAY, DATE, MONTH, YEAR, AND
CENTURY
■ 44 BYTES OF GENERAL PURPOSE RAM
■ PROGRAMMABLE ALARM AND
INTERRUPT FUNCTION (VALID EVEN
DURING BATTERY BACK-UP MODE)
■ WATCHDOG TIMER
■ MICROPROCESSOR POWER-ON RESET
■ BATTERY LOW FLAG
■ POWER-DOWN TIMESTAMP (HT BIT)
■ ULTRA-LOW BATTERY SUPPLY CURRENT
OF 500nA (MAX)
■ PACKAGING INCLUDES A 28-LEAD SOIC
AND SNAPHAT^® TOP (to be ordered
separately)
■ SOIC SNAPHAT PACKAGE PROVIDES
DIRECT CONNECTION FOR A SNAPHAT
TOP WHICH CONTAINS THE BATTERY
AND CRYSTAL
■ SOIC EMBEDDED CRYSTAL PACKAGE
(MX) OPTION
Figure 1. 28-pin SOIC Package
SNAPHAT (SH)
Battery & Crystal
28
1
SOH28 (MH)
Figure 2. 28-pin (300mil) SOIC Package
EMBEDDED Crystal
SOX28 (MX)
September 2004
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