PCF8523T Datasheet, PDF (1/2 Pages) NXP Semiconductors – Save power with small, ultra-efficient RTCs

NXP ultra-low-power
RTC/calendars PCF8523
& PCF2123
Save power with small,
ultra-efficient RTCs
Designed to perform critical time-keeping functions in a range of applications, these small, highly
efficient RTC/calendars fit nearly anywhere and cut power demands by as much as 60 percent.
Key features
} 32.768 kHz quartz crystal
} Resolution: seconds to years
} Freely programmable timer and alarm function with interrupt
} Low backup current: 100 nA typ at V_DD = 2.0 V
and Tamb = 25 °C
} Internal Power-On Reset
} Open drain interrupt and clock output pins
} Programmable offset register for frequency adjustment
} Watchdog timer
Ultra-low-power I²C RTC/calendar PCF8523
} Clock operating voltage: 1.2 V to 5.5 V
} 2 line bi-directional 1 MHz Fast-mode Plus I²C interface
} Battery backup input pin and switch-over circuitry
} Integrated oscillator load capacitors for C_L = 7 and 12.5 pF
} Second countdown timer with interrupt output
Ultra-low-power SPI RTC/calendar PCF2123
} Clock operating voltage: 1.1 to 5.5 V
} 3-line SPI with separate, combinable data I/O
} Serial interface (at V_DD = 1.6 to 5.5 V)
} Free programmable timer and alarm with interrupt capability
} Integrated oscillator load capacitors for C_L = 7 pF
Key applications
} Time-keeping functions
} Battery-powered devices
} Metering
} High-duration timers
} Daily alarms
} Systems with low standby power
The NXP PCF8523 and PCF2123 are CMOS devices that
combine a real-time clock (RTC) and a calendar. Optimized for
low power consumption, they operate at a current of less than
100 nA with a 2.0 V power supply, and consume less than 0.2 μW
of power. The PCF8523 uses an I²C-bus serial interface while the
PCF2123 is equipped with an SPI serial interface.
Both devices are cased in tiny leadless packages that save
space in compact designs. This makes them well suited for
handheld and battery-operated applications, including blood-
pressure monitors and other home-use medical devices, pocket
calculators, portable phones, and PDAs. They are also an
excellent choice for white goods, such as washing machines,
metering units, and other industrial systems. Both devices can
be powered by a very small battery cell or a super-cap.