M41ST84W Datasheet, PDF (1/29 Pages) STMicroelectronics – 3.0/3.3V I2C Serial RTC with Supervisory Functions

M41ST84W
3.0/3.3V I²C Serial RTC
with Supervisory Functions
KEY FEATURES
■ AUTOMATIC BATTERY SWITCHOVER and
DESELECT
– Power-fail Deselect, V_PFD = 2.60V (nom)
– Switchover, V_SO = 2.50V (nom)
■ 400kHz I²C SERIAL INTERFACE
■ 3.0/3.3V OPERATING VOLTAGE
– V_CC = 2.7 to 3.6V
■ ULTRA-LOW BATTERY SUPPLY CURRENT
of 500nA (max)
■ RoHS COMPLIANCE
Lead-free components are compliant with the
RoHS Directive.
Serial RTC Features
■ 400kHz I²C
■ 44 Bytes of General Purpose NVRAM
■ Counters for:
– Seconds, Minutes, Hours, Day, Date,
Month, and Year
– Century
– 10ths/100ths of Seconds
– Clock Calibration register allows
compensation for crystal variations over
temperature
■ Programmable Alarm with Interrupt
– Functions during Battery Back-up Mode
■ Power-down Timestamp (HT Bit)
■ 2.5 to 5.5V Oscillator Operating Voltage
■ 32KHz Oscillator with Integrated Load
Capacitance (12.5pF)
Microprocessor Supervisory Features
■ Programmable Watchdog Timer
– 62.5ms to 128s time-out period
■ Power-on Reset/Low Voltage Detect Output
■ PFI/PFO with 1.25V Reference
Figure 1. 16-pin SOIC Package
16
1
SO16 (MQ)
NVRAM Supervisory Features
■ Non-volatizes External LPSRAM
– Automatically switches to back-up battery
and deselects (write-protects) external
LPSRAM via chip-enable gate
– Power-fail deselect (write protect) voltage,
V_PFD = 2.60V (nom)
– Switchover , V_SO = 2.50V (nom)
■ Battery Low flag
Other Features
■ Programmable Squarewave Generator (1Hz
to 32KHz)
■ –40°C to +85°C Operation
■ Packaged in a 16-lead SOIC
January 2006
Rev 7.0
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