M41ST87WMX6 - STMICROELECTRONICS - 5.0, 3.3, OR 3.0V, 1280 BIT (160
X8) SECURE SERIAL RTC AND NVRAM SUPERVISOR WITH TAMP
Quick Detail:
5.0, 3.3, or 3.0V, 1280 bit (160 x8) Secure Serial RTC and NVRAM
Supervisor with Tamper Detection
Description:
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.
Applications:
■ 5.0, 3.3, OR 3.0V OPERATING VOLTAGE
■ SERIAL INTERFACE SUPPORTS I2C BUS (400kHz)
■ NVRAM SUPERVISOR FOR EXTERNAL LPSRAM
■ 2.5 TO 5.5V OSCILLATOR OPERATING VOLTAGE
■ AUTOMATIC SWITCH-OVER AND DESELECT CIRCUITRY
■ CHOICE OF POWER-FAIL DESELECT VOLTAGES
– M41ST87Y:
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
– M41ST87W:
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
■ TWO INDEPENDENT POWER-FAIL COMPARATORS (1.25V REFERENCE)
■ COUNTERS FOR TENTHS/HUNDREDTHS OF SECONDS, SECONDS, MINUTES,
HOURS, DAY, DATE, MONTH, YEAR, AND CENTURY
■ 128 BYTES OF GENERAL PURPOSE RAM
■ PROGRAMMABLE ALARM AND INTERRUPT FUNCTION (VALID EVEN DURING
BATTERY BACK-UP MODE)
■ PROGRAMMABLE WATCHDOG TIMER
■ UNIQUE ELECTRONIC SERIAL NUMBER (8-BYTE)
■ 32kHz FREQUENCY OUTPUT AVAILABLE UPON POWER-ON
■ MICROPROCESSOR POWER-ON RESET
■ BATTERY LOW FLAG
■ ULTRA-LOW BATTERY SUPPLY CURRENT OF 500nA (TYP)
Specifications:
| Datasheets | M41ST87W/Y |
| Product Photos | 28-SOIC |
| Standard Package | 28 |
| Category | Integrated Circuits (ICs) |
| Family | Clock/Timing - Real Time Clocks |
| Series | - |
| Packaging | Tube |
| Type | Clock/Calendar |
| Features | Alarm, Leap Year, NVSRAM, Square Wave Output, Supervisor, Watchdog
Timer |
| Memory Size | 128B |
| Time Format | HH:MM:SS:hh (24 hr) |
| Date Format | YY-MM-DD-dd |
| Interface | I²C, 2-Wire Serial |
| Voltage - Supply | 2.7 V ~ 3.6 V |
| Voltage - Supply, Battery | 2.5 V ~ 3.6 V |
| Operating Temperature | -40°C ~ 85°C |
| Mounting Type | Surface Mount |
| Package / Case | 28-SOIC (0.295", 7.50mm Width) |
| Supplier Device Package | 28-SOX |
| Catalog Page | 969 (CN081 PDF) |
| Other Names | 497-5370-5
M41ST87WMX6-ND |
