DS1644P Datasheet, PDF (1/13 Pages) Dallas Semiconductor – Nonvolatile Timekeeping RAM

DS1644/DS1644P
Nonvolatile Timekeeping RAM
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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 are
Resident in the Eight Top RAM Locations.
§ Totally Nonvolatile with Over 10 Years of
Operation in the Absence of Power
§ 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
§ DS1644 Only (DIP Module)
Upward Compatible with the DS1643
Timekeeping RAM to Achieve Higher
RAM Density
Standard JEDEC Bytewide 32k x 8 Static
RAM Pinout
§ DS1644P 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
Underwriters Laboratory (UL) Recognized
PIN CONFIGURATIONS
A14 1
A12 2
A7 3
A6 ⁴
A5 5
A4 6
A3 7
A2 8
A1 9
A0 10
DQ0 11
DQ1 ¹²
DQ2 ¹³
GND 14
28
VCC
27
WE
26 A13
25 A8
24
A9
23 A11
22
OE
21 A10
20
CE
19 DQ7
18
DQ6
17
DQ5
16 DQ4
15 DQ3
28-Pin Encapsulated Package
(720-mil Extended)
NC
1
34
NC
NC
2
NC
3
PFO
4
VCC
WE
5
6
33
NC
32
A14
31
A13
30
A12
29
A11
OE
7
CE
DQ7
8
9
DQ6
10
28
A10
27
A9
26
A8
25
A7
DQ5
11
DQ4
12
24
A6
23
A5
DQ3
13
22
A4
DQ2
DQ1
DQ0
GND
14
21
15
16
X1
GND VBAT
X2
20
19
17
18
A3
A2
A1
A0
34-Pin PowerCap Module Board
(Uses DS9034PCX PowerCap)
PowerCap is a registered trademark of Dallas Semiconductor.
ORDERING INFORMATION
PART
VOLTAGE
RANGE (V)
TEMP RANGE PIN-PACKAGE
DS16440120+
5.0
0°C to +70°C 32 EDIP (0.740a)
DS16440-120
5.0
0°C to +70°C 32 EDIP (0.740a)
DS1644P120+
5.0
0°C to +70°C 34 PowerCap*
DS1644P-120
5.0
0°C to +70°C 34 PowerCap*
TOP MARK
DS1644+120
DS1644-120
DS1644P+120
DS1644P-120
*DS9034-PCX, DS9034I-PCX, DS9034-PCX+ required (must be ordered separately).
A “+" indicates a lead-free product. The top mark will include a “+" symbol on lead-free devices.
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REV: 040805