DS1744 Datasheet, PDF (1/18 Pages) Dallas Semiconductor – Y2K-Compliant, Nonvolatile Timekeeping RAMs

DS1744/DS1744P
Y2K-Compliant, Nonvolatile Timekeeping RAMs
www.maxim-ic.com
FEATURES
PIN CONFIGURATIONS
§ Integrated NV SRAM, Real-Time Clock,
Crystal, Power-Fail Control Circuit, and
TOP VIEW
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
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
1 _Dallas 28
2 ^{Semiconductor} 27
3 ^DS1744 26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
VCC
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
Up to the Year 2100
§ Battery Voltage-Level Indicator Flag
§ Power-Fail Write Protection Allows for ±10%
PDIP Module
(700-mil Extended)
V_CC 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^Ò 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
N.C.
N.C.
N.C.
RST
VCC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
1
34
2
Dallas
33
3
Semiconductor
32
4
5
DS1744P
31
30
6
29
7
28
8
27
9
26
10
25
11
24
12
23
13
22
14
21
15
20
16
19
17
X1 GND VBAT X2
18
PowerCap Module Board
(Uses DS9034PCX PowerCap)
N.C.
N.C.
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
§ Also Available in Industrial Temperature
Range: -40°C to +85°C
PowerCap is a registered trademark of Dallas Semiconductor.
Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device
may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata.
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REV: 011204