The DS1744W-120+ is a Y2K compliant, non-volatile timekeeping RAMs in 28 pin EDIP package. This device is a full-function real time clock/calendar (RTC) and 32k x 8 NV SRAM. User access to all registers within the part is accomplished with a byte wide interface. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes and seconds data in 24 hour binary coded decimal (BCD) format. Corrections for the day of the month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur during clock update cycles and prevents time loss as the timekeeping countdown continues unabated by access to time register data. This device contains its own power fail circuitry which deselects device when the VCC supply is in out of tolerance condition.
Supply voltage range from 2.97V to 3.63V
Operating temperature range from 0°C to 70°C
Integrated NV SRAM, real time clock, crystal, power fail control circuit and lithium energy source
Clock registers are accessed identically to the SRAM, access time is 120ns
Totally non-volatile with over 10 years of operation in absence of power
Battery voltage level indicator flag
Power fail write protection allows for ±10% VCC power supply tolerance
Power fail write protection allows for ±10% VCC power supply tolerance
