
Maxim Integrated
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.
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
■ UL Recognized