DS1643 Datasheet, PDF (1/17 Pages) Dallas Semiconductor – Nonvolatile Timekeeping RAM

19-5058; Rev 12/09
DS1643/DS1643P
Nonvolatile Timekeeping RAMs
www.maxim-ic.com
FEATURES
 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.
 Totally Nonvolatile with Over 10 Years of
Operation in the Absence of Power
 Access Times of 70ns and 100ns
 BCD-Coded Year, Month, Date, Day, Hours,
Minutes, and Seconds with Leap Year
Compensation Valid Up to 2100
 Power-Fail Write Protection Allows for ±10%
V_CC Power Supply Tolerance
 Lithium Energy Source is Electrically
Disconnected to Retain Freshness Until Power
is Applied for the First Time
 DS1643 Only (DIP Module)
Standard JEDEC Byte-Wide 8K x 8 RAM
Pinout
 UL Recognized
 DS1643P Only (PowerCap Module Board)
Surface Mountable Package for Direct
Connection to PowerCap Containing
Battery and Crystal
Replaceable Battery (PowerCap)
Power-Fail Output
Pin-for-Pin Compatible with Other Densities of
DS164XP Timekeeping RAM
PIN CONFIGURATIONS
N.C.
TOP VIEW _A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
1
28
2
3
27
DS1643 ₂₆
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
V_CC
WE
CE2
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
Encapsulated DIP
(700-mil Extended)
N.C.
N.C.
N.C.
PFO
V_CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
1
34
2
33
3
DS1643P
32
4
31
5
30
6
29
7
28
8
27
9
26
10
25
11
24
12
23
13
22
14
21
15 _{X1 GND VBAT X2}
16
20
19
17
18
N.C.
N.C.
N.C.
N.C.
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
PowerCap Module Board
(Uses DS9034PCX PowerCap)
ORDERING INFORMATION
PART
VOLTAGE RANGE
(V)
TEMP RANGE
PIN-PACKAGE
DS1643-70+
5.0
0°C to +70°C
28 EDIP (0.740)
DS1643-70
5.0
0°C to +70°C
28 EDIP (0.740)
DS1643-100+
5.0
0°C to +70°C
28 EDIP (0.740)
DS1643-100
5.0
0°C to +70°C
28 EDIP (0.740)
DS1643P-70+
5.0
0°C to +70°C
34-PowerCap*
DS1643P-70
5.0
0°C to +70°C
34-PowerCap*
DS1643P-100+
5.0
0°C to +70°C
34-PowerCap*
DS1643P-100
5.0
0°C to +70°C
34-PowerCap*
*DS9034-PCX, DS9034I-PCX, DS9034-PCX+ required (must be ordered separately).
+Denotes a lead(Pb)-free/RoHS-compliant packaget. The top mark will include a “+” symbol on lead-free devices.
TOP MARK
DS1643+70
DS1643-70
DS1643+100
DS1643-100
DS1643P+70
DS1643P-70
DS1643P+100
DS1643P-100
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