STMicroelectronics M41ST85W Manuals

STMicroelectronics M41ST85W RTC NVRAM Supervisor Datasheet

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.