DS1744 Maxim, DS1744 Datasheet - Page 3

• Manufacturer Part Number: DS1744
• Description: The DS1744 is a full-function, year-2000-compliant (Y2KC), real-time clock/calendar (RTC) and 32k x 8 NV SRAM
• Manufacturer: Maxim

ORDERING INFORMATION
+Denotes a lead(Pb)-free/RoHS-compliant package.
*DS9034-PCX+ or DS9034I-PCX+ required (must be ordered separately).
**A “+” anywhere in the top mark denotes a lead-free device. An “IND” denotes an industrial temperature grade device.
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. 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 DS1744 also contains its own power-fail circuitry that deselects the
device when the V
unpredictable system operation brought on by low V
DS1744-70+
DS1744-70IND+
DS1744W-120+
DS1744W-120IND+
DS1744P-70+
DS1744P-70IND+
DS1744WP-120+
DS1744WP-120IND+
PART
CC
supply is in an out-of-tolerance condition. This feature prevents loss of data from
VOLTAGE
(V)
5.0
5.0
3.3
3.3
5.0
5.0
3.3
3.3
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
0°C to +70°C
DS1744/DS1744P Y2K-Compliant, Nonvolatile Timekeeping RAMs
3 of 16
CC
as errant access and update cycles are avoided.
PIN-PACKAGE
28 EDIP
28 EDIP
28 EDIP
28 EDIP
34 PowerCap*
34 PowerCap*
34 PowerCap*
34 PowerCap*
TOP MARK**
DS1744+70
DS1744+70 IND
DS1744W+120
DS1744W+120 IND
DS1744P+70
DS1744P+70 IND
DS1744WP+120
DS1744WP+120 IND