Introducing NXP’s New CMOS Real-Time Clock and Calendar

One of the leading suppliers of timing products, NXP has plenty of real-time clocks (RTC) to choose from, but none better than the PCF85263A.

The PCF85263A is a CMOS RTC and calendar specially designed for low-power consumption, and which features automatic switching to battery on main power low. It’s equipped with clock output and two independent interrupt signals, two alarms, I2C interface, and quartz crystal collaboration. 

Conveniently, the RTC can be configured as a stop-watch, and three time log registers which are triggered from battery switch-over as well as input driven event. 

The PCF85263 can be used for all standard RTC functions — this includes tracking time and data or acting as a reference timer. Additionally, as a means of supporting power management, the PCF85263 can be used to wake a microcontroller from hibernation mode, and in systems that use a PLL, it can act as a system reference clock for the PLL input. 

Also worth noting: NXP’s PCF85263 can be used as a WatchDog timer, or as an activation timer to start measurements or initiate other functions.

A brief summary of PCF85263A’s features and benefits: 
• 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 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

Among the applications to which this impressive technology can be applied: 
• 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

Check out this informative video detailing the PCF85263A and NXP’s other RTCs.

To learn more, or to otherwise order the PCF85263A, visit NXP’s product page at DigiKey.