| Integrated 64k NV SRAM, real-time clock, crystal, power-fail control circuitry, and lithium energy cell Tracks seconds, minutes, hours, days, dates, months, years, and leap years, valid to year 2100 Clock and RAM registers accessed identically Two external interrupts usable as watchdog timer and/or RTC alarm Power-on reset Low-battery warning Clock accuracy better than ±1 min/month at 25°C Voltage/power-fail tolerances: 3.3V ±10% (DS1543W)5V ±10% (DS1543)Operating range: 0°C to 70°C >10 years operation without system power Freshness seal (lithium disconnected until first power-up) |