M41ST85W is a 3.0/3.3 V I2C combination serial RTC, NVRAM supervisor and microprocessor supervisor. It features automatic battery switchover and WRITE protection for internal serial RTC and external low power SRAM (LPSRAM). It also features 400 kHz I2C serial interface, 3.0/3.3 V operating voltage VCC=2.7 to 3.6 V, ultralow battery supply current of 500 nA (max), RoHS compliant, lead-free second level interconnect and so on.
The M41ST85W is a combination serial real-time clock, microprocessor supervisor, and NVRAM supervisor built in a low-power CMOS SRAM process. It features a 400 kHz I2C serial interface, 44 bytes of general-purpose NVRAM, and 20 memory-mapped RTC registers configured in binary coded decimal (BCD) format.
Key features include automatic battery switchover and write-protect for both the internal RTC and external low-power SRAM (LPSRAM). The device includes a programmable watchdog with a time-out period of 62.5 ms to 128 s, an early power-fail warning circuit with a 1.25 V precision reference, and a programmable squarewave generator ranging from 1 Hz to 32 kHz. It operates with a supply voltage of 2.7 to 3.6 V and supports temperatures from -40°C to +85°C.
| Operating voltage | 2.7 to 3.6 V |
|---|---|
| Supply current (max) | 500 nA |
| NVRAM size | 44 bytes |
| RTC registers | 20 |
| Watchdog time-out period | 62.5 ms to 128 s |
| Squarewave output frequency | 1 Hz to 32 KHz |
| Operating temperature | -40°C to +85°C |
The device operates at 3.0/3.3 V with a Veco range of 2.7 to 3.6 V.
The M41ST85W provides 44 bytes of general-purpose NVRAM.
The ultralow battery supply current is a maximum of 500 nA.
The programmable watchdog has a time-out period ranging from 62.5 ms to 128 s.