DS1743/DS1743P
Y2K-Compliant, Nonvolatile Timekeeping
RAMs
FEATURES
PIN CONFIGURATIONS
. 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.
TOP VIEW
N.C.
A12
A7
A6
A5
A4
A3
A2
A1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
VCC
WE
CE2
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DS1743
. 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
A0
DQ0
DQ1
DQ2
GND
28-Pin Encapsulated Package
(28 PIN 740)
. 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
34
N.C.
N.C.
N.C.
1
2
3
N.C.
N.C.
N.C.
DS1743P
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
N.C.
A12
A11
A10
A9
4
5
6
RST
VCC
WE
7
OE
8
CE
A8
9
DQ7
A7
A6
A5
A4
A3
A2
A1
A0
10
11
12
13
14
15
16
17
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
GND VBAT
X1
X2
Replaceable Battery (PowerCap)
Power-On Reset Output
34-Pin PowerCap Module Board
(Uses DS9034PCX+ or DS9034I-PCX+ PowerCap)
Pin-for-Pin Compatible with Other Densities
of DS174XP Timekeeping RAM
.
Underwriters Laboratories (UL) Recognized
to Prevent Charging of the Internal Lithium
Battery
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.maximintegrated.com/errata.
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