The DS1682 input logic thresholds for SDA and SCL are defined by the "Input Trip Point" parameter on page 2 of the datasheet (19-6836). The input low threshold (i.e. VIL(MAX)) is 30% of VCC. The input high threshold (i.e. VIH(MIN)) is 70% of VCC.
DS1682
Production
The DS1682 is an integrated elapsed-time recorder containing a factory-calibrated, temperature-compensated RC time base that eliminates the need for an...
Datasheet
DS1682 on Analog.com