M41ST85 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
M41ST85
STMicroelectronics
'M41ST85' PDF : 41 Pages View PDF
M41ST85W
3.0/3.3V I2C combination serial RTC, NVRAM
supervisor and microprocessor supervisor
Features
ā Automatic battery switchover and WRITE
protect for:
ā Internal serial RTC and
ā External low power SRAM (LPSRAM)
ā 400kHz I2C serial interface
ā 3.0/3.3V operating voltage
ā VCC = 2.7 to 3.6V
ā Ultra-low battery supply current of 500nA (max)
ā RoHS compliant
ā Lead-free second level interconnect
Serial RTC features
ā 400kHz I2C
ā 44 bytes of general purpose NVRAM
ā Counters for:
ā Seconds, minutes, hours, day, date, month,
and year
ā Century
ā 10ths/100ths of seconds
ā Clock calibration register allows
compensation for crystal variations over
temperature
ā Programmable alarm with repeat modes
ā Functions in battery back-up mode
ā Power-down timestamp (HT Bit)
ā 2.5 to 5.5V oscillator operating voltage
Microprocessor supervisor features
ā Programmable watchdog
ā 62.5ms to 128s time-out period
ā Early power-fail warning circuit (PFI/PFO) with
1.25V precision reference
SNAPHAT (SH) battery & crystal
28
1
SOH28 (MH)
Embedded crystal
SOX28 (MX)
ā Power-on reset/low voltage detect
ā Open drain reset output
ā Reset voltage, VPFD = 2.60V (nom)
ā Two reset input pins
ā Watchdog can be steered to reset output
NVRAM supervisor features
ā Non-volatizes external LPSRAM
ā Automatically switches to back-up battery
and deselects (write-protects) external
LPSRAM via chip-enable gate
ā Power-fail deselect (write protect) voltage,
VPFD = 2.60V (nom)
ā Switchover , VSO = 2.50V (nom)
ā Battery monitor (battery low flag)
Other features
ā Programmable squarewave generator (1Hz to
32KHz)
ā ā40Ā°C to +85Ā°C Operation
ā Package options:
ā 28-lead SNAPHATĀ® IC (SOH28) SNAPHAT
battery/crystal top to be ordered separately
ā 28-lead embedded crystal SOIC (SOX28)
October 2007
Rev 9
1/41
www.st.com
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