MAXIM INTEGRATED / ANALOG DEVICES DS1554WP-120+ Datasheet & Stock

The DS1554WP-120+ from Maxim Integrated Products is a 256K, non-volatile, Y2K-compliant timekeeping RAM in 34 pin PowerCap package. This full function, year 2000 compliant (Y2KC), real time clock/calendar (RTC) has RTC alarm, watchdog timer, power-on reset, battery monitor and 32K x 8 non-volatile static RAM. User access to all registers within DS1554 is accomplished with byte wide 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 are made automatically. The RTC registers are double buffered into an internal and external set. Clock/calendar updates to external set of registers can be disabled and enabled to allow user to access static data. Assuming internal oscillator is turned on, internal set of registers is continuously updated, this occurs regardless of external registers settings that accurate RTC information is always maintained.




Supply voltage is 3.3V ±10%, active supply current is 10mA at VCC = 3.3V ±10%

Operating temperature range from 0°C to 70°C

Integrated NV SRAM, RTC, crystal, power fail control circuit and lithium energy source

Clock registers are accessed identically to static RAM, registers reside in the 16 top RAM locations

Totally non-volatile with over 10 years of operation in absence of power

Precision power-on reset, programmable watchdog timer and RTC alarm

Battery voltage level indicator flag, user has direct access to external set

Power fail write protection allows for ±10% VCC power supply tolerance

Lithium energy source is electrically disconnected to retain freshness

2.75V to 2.97V write protection voltage, 120ns read cycle time, 120ns write cycle time