With the introduction of the DS3231 extremely accurate, I2C*-compatible, integrated RTC/TCXO/crystal, Dallas Semiconductor has redefined the accuracy expectations of a stand-alone, real-time clock. The DS3231 provides ±3.5 ppm of accuracy over the industrial temperature range (-40°C to +85°C). The device achieves this level of accuracy by measuring the device temperature every 64 seconds (64s) and adjusting the load capacitance of the crystal to approach 0ppm accuracy at that specific temperature.