PCF8523T/1,118

PCF8523T/1,118 is a CMOS Real-Time Clock (RTC) and calendar optimized for low power consumption. Data is transferred serially via the I2C-bus with a maximum data rate of 1000 kbit/s. Alarm and timer functions are available with the possibility to generate a wake-up signal on an interrupt pin. An offset register allows fine-tuning of the clock. The PCF8523 has a backup battery switch-over circuit, which detects power failures and automatically switches to the battery supply when a power failure occurs. Typical applications include time keeping application, battery powered devices and metering.

• Provides year, month, day, weekday, hours, minutes, and seconds based on a 32.768KHz quartz crystal
• Resolution: seconds to years
• Clock operating voltage range from 1.0V to 5.5V
• Low backup current of typical 150nA at VDD = 3.0V and Tamb = 25°C
• 2 line bidirectional 1MHz Fast-mode Plus (Fm+) I2C interface, read D1h, write D0h2
• Battery backup input pin and switch-over circuit
• Freely programmable timer and alarm with interrupt capability
• Selectable integrated oscillator load capacitors for CL = 7pF or CL = 12.5pF
• Oscillator stop detection function, internal power-on reset (POR)
• Open-drain interrupt or clock output pins, programmable offset register for frequency adjustment