M41T56M6F

M41T56M6F is a low-power, serial real-time clock (RTC) with 56 bytes of NVRAM. A built-in 32,768Hz oscillator (external crystal controlled) and the first 8 bytes of the RAM are used for the clock/calendar function and are configured in binary-coded decimal (BCD) format. Addresses and data are transferred serially via a two-line, bidirectional bus. The built-in address register is incremented automatically after each WRITE or READ data byte. The M41T56 clock has a built-in power sense circuit that detects power failures and automatically switches to the battery supply during power failures. The energy needed to sustain the RAM and clock operations can be supplied from a small lithium coin cell.

• Counters for seconds, minutes, hours, day, date, month, years, and century
• Serial interface supports I²C bus (100KHz protocol), automatic leap year compensation
• Automatic power-fail detect and switch circuitry, 56 bytes of general purpose RAM
• Software clock calibration to compensate crystal deviation due to temperature
• Battery supply current is 450nA typical at (TA = 25°C, VCC = 0V, oscillator ON, VBAT = 3V)
• Input leakage current is ±1µA maximum at (0V ≤ VIN ≤ VCC)
• Supply current is 300µA maximum at (switch frequency = 100KHz)
• Resonant frequency is 32.768KHz typical
• Load capacitance is 12.5pF typical
• Operating temperature range from -40°C to 85°C, SO8 package