DESCRIPTION

The DS1744 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 32k x 8 NV SRAM. User access to all registers within the DS1744 is accomplished with a byte-wide interface as shown in Figure 1. The RTC information and control bits reside in the eight uppermost RAM locations. The RTC registers contain century, year, month, date, day, hours, minutes, and seconds data in 24-hour BCD format. Corrections for the date of each month and leap year are made automatically.

FEATURES

■ Integrated NV SRAM, Real-Time Clock, Crystal, Power-Fail Control Circuit, and Lithium Energy Source

■ Clock Registers are Accessed Identically to the Static RAM. These Registers are Resident in the Eight Top RAM Locations.

■ Century Byte Register (i.e., Y2K Compliant)

■ Totally Nonvolatile with Over 10 Years of Operation in the Absence of Power

■ BCD-Coded Century, Year, Month, Date, Day, Hours, Minutes, and Seconds with Automatic Leap-Year Compensation Valid Up to the Year 2100

■ Battery Voltage-Level Indicator Flag

■ Power-Fail Write Protection Allows for ±10 VCC Power-Supply Tolerance

■ Lithium Energy Source is Electrically

Disconnected to Retain Freshness Until Power is Applied for the First Time

■ DIP Module Only

Standard JEDEC Byte-Wide 32k x 8 Static RAM Pinout

■ PowerCap® Module Board Only

Surface-Mountable Package for Direct Connection to PowerCap Containing Battery and Crystal

Replaceable Battery (PowerCap)

Power-On Reset Output

Pin-for-Pin Compatible with Other Densities of DS174xP Timekeeping RAM

■ Also Available in Industrial Temperature Range: -40°C to +85°C