The DS1558W+ is a watchdog clock with NVRAM control in 48 pin TQFP package. The device operates at 3.3V and it is a full function, year 2000 compliant (Y2KC), real time clock/calendar with RTC alarm, watchdog timer, power-on reset, battery monitor and NV SRAM controller. User access to all registers within DS1558W is accomplished with a bytewide interface. The RTC registers contain century, year, month, date, day, hours, minutes and seconds data in 24 hour BCD format. Corrections for day of month and leap year compensation valid up to the year 2100. The device maps RTC registers into SRAM address space and constantly monitors A0-A18. The DS1558W provides greater than 10 years of timekeeping and data retention in the absence of power with small lithium coin cells and low leakage SRAM. It can be used with SRAMs up to 524,272 addresses. The DS1558W has interrupt (active-low IRQ/FT) and reset (active-low RST) outputs that can be used to control CPU activity.
● Supply voltage range from 2.97V to 3.63V
● Operating temperature range from -40°C to 85°C
● Battery voltage level indicator flag
● Power fail write protection allows for ±10% VCC power supply tolerance
● UL recognized
● 2.88V write protection voltage, 120ns read cycle time and 120ns write cycle time
● Greater than 10 years of timekeeping and data retention in absence of power
● Precision power-on reset
● Programmable watchdog timer and RTC alarm
● Active supply current of 4mA and CMOS standby current of 1mA
