1. General description
The PCF85263A is a CMOS1 Real-Time Clock (RTC) and calendar optimized for low
power consumption and with automatic switching to battery on main power loss. The RTC
can also be configured as a stop-watch (elapsed time counter). Three time log registers
triggered from battery switch-over as well as input driven events. Featuring clock output
and two independent interrupt signals, two alarms, I2C interface and quartz crystal
calibration.
For a selection of NXP Real-Time Clocks, see Table 72 on page 90
2. Features and benefits
 UL Recognized Component (PCF85263ATL)
 Provides year, month, day, weekday, hours, minutes, seconds and 100th seconds
based on a 32.768 kHz quartz crystal
 Stop-watch mode for elapsed time counting. From 100th seconds to 999999 hours
 Two independent alarms
 Battery back-up circuit
 WatchDog timer
 Three timestamp registers
 Two independent interrupt generators plus predefined interrupts at every second,
minute, or hour
 Frequency adjustment via programmable offset register
 Clock operating voltage: 0.9 V to 5.5 V
 Low current; typical 0.28 A at VDD = 3.0 V and Tamb = 25 C
 400 kHz two-line I2C-bus interface (at VDD = 1.8 V to 5.5 V)
 Programmable clock output for peripheral devices (32.768 kHz, 16.384 kHz,
8.192 kHz, 4.096 kHz, 2.048 kHz, 1.024 kHz, and 1 Hz)
 Configurable oscillator circuit for a wide variety of quartzes: CL = 6 pF, CL = 7 pF, and
CL = 12.5 pF
3. Applications
 Printers and copiers
 Electronic metering
 Digital cameras
 White goods
 Elapsed time counter
 Network powered devices
 Battery backed up systems
 Data loggers
 Digital voice recorders
 Mobile equipment
 Accurate high duration timer