5.0, 3.3, or 3.0V, 1280 bit (160 x8) Secure Serial RTC and NVRAM Supervisor with Tamper Detection
The M41ST87Y/W Serial TIMEKEEPER®/Controller SRAM is a low power 1280-bit, static CMOS SRAM organized as 160 bytes by 8 bits. A built-in 32.768 kHz oscillator (internal crystal-controlled) and 8 bytes of the SRAM (see Table 7., page 25) are used for the clock/calendar function and are configured in binary coded decimal (BCD) format.
An additional 11 bytes of RAM provide calibration, status/control of Alarm, Watchdog, Tamper, and Square Wave functions. 8 bytes of ROM and finally 128 bytes of User RAM are also provided. Addresses and data are transferred serially via a two line, bi-directional I2C interface. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41ST87Y/W has a built-in power sense circuit which detects power failures and automatically switches to the battery supply when a power failure occurs. The energy needed to sustain the SRAM and clock operations can be supplied by a small lithium buttoncell supply when a power failure occurs.
Functions available to the user include a non-volatile, time-of-day clock/calendar, Alarm interrupts, Tamper Detection, Watchdog Timer, and programmable Square Wave output. Other features include a Power-On Reset as well as two additional debounced inputs (RSTIN1 and RSTIN2) which can also generate an output Reset (RST). The eight clock address locations contain the century, year, month, date, day, hour, minute, second and tenths/hundredths of a second in 24 hour BCD format. Corrections for 28, 29 (leap year), 30 and 31 day months are made automatically.
â– 5.0, 3.3, OR 3.0V OPERATING VOLTAGE
â– SERIAL INTERFACE SUPPORTS I2C BUS (400kHz)
â– NVRAM SUPERVISOR FOR EXTERNAL LPSRAM
â– 2.5 TO 5.5V OSCILLATOR OPERATING VOLTAGE
â– AUTOMATIC SWITCH-OVER AND DESELECT CIRCUITRY
â– CHOICE OF POWER-FAIL DESELECT VOLTAGES
VCC = 4.75 to 5.5V;
THS Bit = '1': 4.50V ≤ VPFD ≤ 4.75V
VCC = 4.5 to 5.5V;
THS Bit = '0': 4.20V ≤ VPFD ≤ 4.50V
VCC = 3.0 to 3.6V;
THS Bit = '1': 2.8V ≤ VPFD ≤ 3.0V
VCC = 2.7 to 3.6V;
THS Bit = '0': 2.55V ≤ VPFD ≤ 2.70V
â– TWO INDEPENDENT POWER-FAIL COMPARATORS (1.25V REFERENCE)
â– COUNTERS FOR TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES,
HOURS, DAY, DATE, MONTH, YEAR, AND CENTURY
â– 128 BYTES OF GENERAL PURPOSE RAM
â– PROGRAMMABLE ALARM AND INTERRUPT FUNCTION (VALID EVEN DURING BATTERY BACK-UP MODE)
â– PROGRAMMABLE WATCHDOG TIMER
â– UNIQUE ELECTRONIC SERIAL NUMBER (8-BYTE)
â– 32kHz FREQUENCY OUTPUT AVAILABLE UPON POWER-ON
â– MICROPROCESSOR POWER-ON RESET
â– BATTERY LOW FLAG
â– ULTRA-LOW BATTERY SUPPLY CURRENT OF 500nA (TYP)
Integrated Circuits (ICs)
Clock/Timing - Real Time Clocks
Alarm, Leap Year, NVSRAM, Square Wave Output, Supervisor, Watchdog Timer
HH:MM:SS:hh (24 hr)
I²C, 2-Wire Serial
Voltage - Supply
2.7 V ~ 3.6 V
Voltage - Supply, Battery
2.5 V ~ 3.6 V
-40°C ~ 85°C
Package / Case
28-SOIC (0.295", 7.50mm Width)
Supplier Device Package
969 (CN081 PDF)
Warranty :180 days !
Free shipping: Order over $1000 win a free shipment fee
(goods weight below 3Kg) ,during 20130901-20130930 .
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