NXP USA Inc. PCF2129T/2,518

Description
The PCF2129 is a CMOS Real Time Clock (RTC) and calendar with an integrated Temperature Compensated Crystal (Xtal) Oscillator (TCXO) and a 32.768 kHz quartz crystal optimized for very high accuracy and very low power consumption. It has a selectable 12C-bus or SPI-bus, a backup battery switch-over circuit, a programmable watchdog function, a timestamp function, and many other features.

Features
Operating temperature range from -40 °C to 85 °C
Temperature Compensated Crystal Oscillator (TCXO) with integrated capacitors
Typical accuracy:
PCF2129AT: ±3 ppm from -15 °C to 60 °C
PCF2129T: ±3 ppm from -30 °C to 80 °C
Integration of a 32.768 kHz quartz crystal and oscillator in the same package
Provides year, month, day, weekday, hours, minutes, seconds, and leap year correction
Timestamp function with interrupt capability
Detection of two different events on one multilevel input pin (for example, for tamper detection)
Two line bidirectional 400 kHz Fast-mode I²C-bus interface
3 line SPI-bus with separate data input and output (maximum speed 6.5 Mbit/s)
Battery backup input pin and switch-over circuitry
Battery backed output voltage
Battery low detection function
Power-On Reset Override (PORO)
Oscillator stop detection function
Interrupt output (open-drain)
Programmable 1 second or 1 minute interrupt
Programmable watchdog timer with interrupt
Programmable alarm function with interrupt capability
Programmable square output

Applications
Industrial applications
Automotive applications
Medical applications
Consumer applications