The PCA2131 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 ultra-low power consumption. The PCA2131 features: * Automotive qualified AEC-Q100 grade 2 * Operating temperature range from -40 °C up to 105°C * Clock operational up to 125 °C * Selectable I²C-bus or SPI-bus interfaces for full flexibility when selecting the associated MCU/MPU * Backup battery input and switch-over circuit, allowing the RTC to keep track of the time, even when the main power supply is removed * Calendar capabilities to keep tracking of the time from years down to 1/100 seconds. * Up to 4 time stamp registers, which can be associated to time stamp input in order to register tampering events * Up to 2 interrupt outputs to enable/disable systems to reduce the overall current consumption