The DS1743 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 8k x 8 nonvolatile static RAM. User access to all registers within the DS1743 is accomplished with a bytewide
interface as shown in Figure 1 in the full data sheet. 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 binary-coded decimal (BCD) format. Corrections for the day of the month and leap year are made automatically. The RTC clock registers are double buffered to avoid access of incorrect data that can occur
during clock update cycles. The double-buffered system also prevents time loss as the timekeeping countdown continues unabated by access to time register data. The DS1743 also contains its own power-fail circuitry, which deselects the device when the VCC supply is in an out-of-tolerance condition. When
VCC is above VPF, the device is fully accessible. When VCC is below VPF, the internal active-low CE signal is forced high, preventing any access. When VCC rises above VPF, access remains inhibited for TREC, allowing time
for the system to stabilize. These features prevent loss of data from unpredictable system operation brought on by low VCC as errant access and update cycles are avoided.
关键特性
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 Reside in the Eight Top RAM Locations.
Century Byte Register
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 through 2099
Low-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 Bytewide 8k 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
Underwriters Laboratories (UL) Recognized to Prevent Charging of the Internal Lithium Battery
Notes: **This pricing is BUDGETARY, for comparing similar parts. Prices are in
U.S. dollars and subject to change. Quantity pricing may vary
substantially and international prices may differ due to local
duties, taxes, fees, and exchange rates. For volume-specific prices
and delivery, please see the price and availability page
or contact an authorized distributor.
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