DS1742W-120

The DS1742 integrated NV SRAM and real-time clock can operate continuously for the life of the equipment it is installed in when the V CC supply is not present. The life expectancy is specified to be 10 years at 25 °C with the internal clock oscillator running in the absence of V CC power. However, the actual life expectancy of the DS1742 will be much longer than 10 years since no lithium battery energy is consumed when V CC is present. The lithium power source in the DS1742 is designed to provide energy for clock activity and data retention, ensuring continuous operation even without V CC power.

User access to all registers within the DS1742 is accomplished through the device architecture, which allows ripple-through access to any of the address locations in the NV SRAM. Valid data will be available at the DQ pins within a specific time after the last address input is stable, provided that the CE, and OE access times and states are satisfied. If CE or OE access times and states are not met, valid data will be available at the latter of chip enable access or at output.

The data stored in the RTC registers of the DS1742 real-time clock is in 24-hour BCD format.