RTC with integrated NVSRAM — what it is and where it fits
The Maxim DS1744-70IND+ is a real-time clock (RTC) with 32KB of nonvolatile SRAM integrated into a single 28-pin EDIP module. It keeps time in YY-MM-DD-dd date format and HH:MM:SS (24-hour) time format via a parallel interface, and handles leap-year and Y2K rollover automatically. The 32KB NVSRAM retains data without external battery management — the module itself contains the SRAM and the power-fail control circuitry, so the backup battery (typically a lithium coin cell) connects directly to the module's Vbat pin. This part is rated for industrial environments with an operating temperature range of -40°C to 85°C, making it a fit for outdoor telecom gear, factory-floor controllers, data loggers, and any embedded system that needs a reliable timebase plus nonvolatile storage in one through-hole package.
What the ratings mean for your BOM
The 32KB NVSRAM holds configuration data, event logs, or calibration constants through a power loss. The 4mA timekeeping current at 5V is low enough for years of backup operation.
Lifecycle and supply reality
There is no NRND or EOL notice on this variant. It is ROHS3 compliant.