The KR3225Y series is an ultra miniature real time clock module with a 3.2mm x 2.5mm dimension I2C-BUS serial interface. Frequency selection is available from 32.768kHz, 1024Hz, 32Hz, and 1Hz. Various functions include a full calendar, alarm, and timer. It also features low current consumption with time keeping mode. The frequency stability is tight +/-5 ppm over -40 to +85°C, thanks to its built-in digital TCXO. An application manual is also available.