The M41ST84W Serial Real-Time Clock is built in a low power CMOS SRAM process. It has a 64-byte memory space with 44 bytes of NVRAM and 20 memory-mapped RTC registers (see Table 3., page 14). The RTC registers are configured in binary coded decimal (BCD) format.A built-in, low power 32.768kHz oscillator (external crystal controlled) provides the time base for the timekeeping and calendar functions.The basic clock/calendar functions are handled by the first eight RTC registers, while the other twelve bytes provide status/control for the Alarm, Watchdog,and Square Wave functions.Addresses and data are transferred serially via the two line, bi-directional I²C interface. The built-in address register is incremented automatically after each WRITE or READ data byte.
The M41ST84W 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 button-cell supply when a power failure occurs. Functions available to the user include a non-volatile, time-of-day clock/calendar, Alarm interrupts, Watchdog Timer and programmable Square Wave output. Other features include a Power-On Reset as well as an additional input (RSTIN) 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 - valid until year 2100), 30 and 31 day months are made automatically. The M41ST84W is supplied in a 16-lead SOIC package.
Ordering Model | Package | RoHS Compliance Grade | Marketing Status | Memory Organization | Supply Voltage(Vcc) | Supply Voltage(Vcc) | RST Threshold(VPFD) | General Description | Programmable Alarms | Watchdog Timer | Power Fail Comparator(PFI/PFO) | RSTin Inputs(RSTin) | Square Wave Output(SQW) | Operating Range | Battery Switchover(VSO) | Battery Low Detect(BL) | Packing Type |
min | max | typ | |||||||||||||||
V | V | V | |||||||||||||||
M41ST84WMQ6E | SO16 | Ecopack1 | Active | 512b (64 x 8) | 2.7 | 3.3 | 2.6 | Serial RTC SUPERVISOR | Yes | Yes | Yes | Yes | Yes | Industrial | Yes | Yes | Tube |
M41ST84WMQ6F | SO16 | Ecopack1 | Active | 512b (64 x 8) | 2.7 | 3.3 | 2.6 | Serial RTC SUPERVISOR | Yes | Yes | Yes | Yes | Yes | Industrial | Yes | Yes | Tape And Reel |