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Data Sheet

FULL DATA SHEET (PDF, 360kB) Download   E-Mail

Description

The DS1244 256k NV SRAM with a Phantom clock is a fully static nonvolatile RAM (NV SRAM) (organized as 32k words by 8 bits) with a built-in real-time clock. The DS1244 has a self-contained lithium energy source and control circuitry, which constantly monitors VCC for an out-of-tolerance condition. When such a condition occurs, the lithium energy source is automatically switched on and write protection is unconditionally enabled to prevent garbled data in both the memory and real-time clock. The phantom clock provides timekeeping information for hundredths of seconds, seconds, minutes, hours, days, date, months, and years. The date at the end of the month is automatically adjusted for months with fewer than 31 days, including correction for leap years. The phantom clock operates in either 24-hour or 12-hour format with an AM/PM indicator.

Key Features

Real-Time Clock (RTC) Keeps Track of Hundredths of Seconds, Minutes, Hours, Days, Date of the Month, Months, and Years 32k x 8 NV SRAM Directly Replaces Volatile Static RAM or EEPROM Embedded Lithium Energy Cell Maintains Calendar Operation and Retains RAM Data Watch Function is Transparent to RAM Operation Month and Year Determine the Number of Days in Each Month; Valid Up to 2100 Full 10% Operating Range Operating Temperature Range: 0°C to +70°C Over 10 Years of Data Retention in the Absence of Power Lithium Energy Source is Electrically Disconnected to Retain Freshness Until Power is Applied for the First Time DIP Module Only Standard 28-Pin JEDEC Pinout PowerCap Module Board Only Surface mountable package for direct connection to PowerCap containing battery and crystal Replaceable battery (PowerCap) Pin-for-pin compatible with DS1248P and DS1251P Available in Lead-Free Package Underwriters Laboratories (UL®) Recognized

Application Notes

Application Note 52: Using the Dallas Phantom Real-Time Clocks (RTCs) - DS1244P Application Note 504: Design Considerations for Dallas Semiconductor Real-Time Clocks - DS1244 Application Note 507: PowerCap Package Allows for Density Upgrades, Surface Mount Assembly - DS1244 Application Note 509: Using the SmartWatch/Phantom Clocks with a Microcontroller - DS1244

Evaluation Kits

none

Design Guides

REAL-TIME CLOCKS (PDF) NONVOLATILE MEMORY (PDF)

Reliability Reports

Reliability Report: DS1244.pdf DS1244P.pdf Underwriters Laboratories (UL®) Recognized

Software/Models

none

Ordering Information
Notes: Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.
Devices: 1-8 of 8
DS1244	Free Sample	Buy	Package: TYPE PINS FOOTPRINT   DRAWING CODE/VAR *	Temp	RoHS/Lead-Free? Materials Analysis
DS1244W-120			0 pin; Use pkgcode/variation: MDT28-4*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1244Y-70			0 pin; Use pkgcode/variation: MDT28-4*	0°C to +70°C	RoHS/Lead-Free: No Materials Analysis
DS1244W-120+			0 pin; Use pkgcode/variation: MDT28+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1244Y-70+			0 pin; Use pkgcode/variation: MDT28+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1244W-120IND+			0 pin; Use pkgcode/variation: MDT28+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1244WP-120+			0 pin; Use pkgcode/variation: PC2+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1244YP-70+			0 pin; Use pkgcode/variation: PC2+4*	0°C to +70°C	RoHS/Lead-Free: Lead Free Materials Analysis
DS1244WP-120IND+			0 pin; Use pkgcode/variation: PC2+4*	-40°C to +85°C	RoHS/Lead-Free: Lead Free Materials Analysis

More Information

Real-Time Clock Design Guide (PDF)

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