Active-production RTC with integrated NVSRAM
The DS1501WZ+T&R is a parallel-interface real-time clock (RTC) from Analog Devices, classified under Microcontrollers & Processors (MCU / MPU / DSP) for its integrated timekeeping and 256-byte NVSRAM.
Battery-backup and timekeeping current
The RTC accepts a separate battery supply from 2.5V to 3.7V, maintaining timekeeping and NVSRAM retention when the main 3V–3.6V rail drops. Maximum timekeeping current draw is 4mA across the full supply range — this is the worst-case figure for sizing the backup battery capacity in an unpowered state.
Feature set and interface
Beyond basic clock/calendar functions, the DS1501WZ+T&R integrates an alarm, a square-wave output, a watchdog timer, and a leap-year compensation circuit. The Y2K compliance flag ensures the date rollover past 1999 is handled correctly — relevant for embedded systems with long service lives. The parallel interface provides direct byte-wide access to the timekeeping and NVSRAM registers, which simplifies firmware integration on MCUs with a parallel memory bus but consumes more GPIO than an I²C/SPI RTC.
Housed in a 28-SOIC wide-body package (0.295-inch body width, 7.50mm) with surface-mount termination.