NXP Semiconductors PCF85263A

The PCF85263A is a CMOS 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). It features three time log registers triggered from the battery switch, as well as over input-driven events. It also features clock output and two independent interrupt signals, two alarms, an I²C interface, and quartz crystal calibration.

Key features

• Ultra small package
• Low current; typical 0.28 µA at VDD = 3.0 V and Tamb = 25 °C
• Wide voltage range 1.8V to 5.5V
• Tamper pin & timestamp register

Additional features

• UL Recognized Component (PCF85263ATL)
• Provides year, month, day, weekday, hours, minutes, seconds, and 100^th seconds based on a 32.768 kHz quartz crystal
• Stop-watch mode for elapsed time counting. From 100^th 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 μA 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

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

Available tools

• The OM13510 is the ideal evaluation and demo board of the PCF85263A. It can be used in the design phase of any project. Just the supplies and the bus must be connected.
• On the OM13510 the I²C RTC PCF85263ATL is mounted together with a quartz crystal, a lithium battery plus the blocking capacitor, buffering the supply voltage. A push button allows activating the time stamp. All signals are accessible on a line of pins, overcoming the difficulties to contact the tiny package directly.