M41T81ME – STMicroelectronics

The STMicroelectronics M41T81ME is a low-power serial real-time clock (RTC) with a built-in crystal oscillator and battery switchover. It provides a complete time-of-day and calendar function, including automatic leap year compensation valid up to the year 2099. This device communicates through an I2C serial interface and features a programmable square wave output. The M41T81ME operates typically within a 2.0V to 5.5V range, but the output voltage is rated at 3.3V. The output current is rated at 1mA. It is available in an 8-pin SOIC SMD package, suitable for automated assembly. Its operating temperature range spans –40°C to 85°C, making it suitable for industrial and automotive applications. Common use cases include data logging, embedded systems requiring time-stamping, and power management applications. Its integrated crystal and battery switchover simplifies design and reduces board space, offering a cost-effective timing solution.