Owner manual

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FEATURES
§ Real-time clock keeps track of hundredths of
seconds, minutes, hours, days, date of the
month, months, and years
§ 512k x 8 NV SRAM directly replaces
volatile static RAM or EEPROM
§ Embedded lithium energy cell maintains
calendar operation and retains RAM data
§ Watch function is transparent to RAM
operation
§ Month and year determine the number of
days in each month; valid up to 2100
§ Over 10 years of data retention in the
absence of power
§ Full 10% operating range
§ Lithium energy source is electrically
disconnected to retain freshness until power
is applied for the first time
§ DIP Module only
– Standard 32-pin JEDEC pinout
– Upward comparable with the DS1248
§ PowerCap
®
Module Board only
– Surface mountable package for direct
connection to PowerCap containing
battery and crystal
– Replaceable battery (PowerCap)
– Pin for pin compatible with other densities
of DS124XP phantom clocks
PIN ASSIGNMENT
DS1251/DS1251P
4096k NV SRAM with Phantom Clock
www.maxim-ic.com
13
1
2
3
4
5
6
7
8
9
10
11
12
14
31
32-Pin Encapsulated Package
740mil Flush
A14
A7
A5
A4
A3
A2
A1
A0
DQ1
DQ0
V
CC
A
15
A
17
WE
A
13
A
8
A
9
A
11
OE
A
10
CE
DQ7
DQ5
DQ6
32
30
29
28
27
26
25
24
23
22
21
19
20
A16
A12
A6
A18/RST
DQ2
GND
15
16
18
17
DQ4
DQ3
1
RST
2
3
A15
A16
NC
V
CC
WE
OE
CE
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
GND
4
5
6
7
8
9
10
11
12
13
14
15
16
17
A
17
A
14
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
A
13
A
12
A
11
A
10
A
9
A
8
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
34
A
18
X1 GND
V
BAT
X2
34-Pin PowerCap Module Board
(Uses DS9034PCX PowerCap)
PowerCap is a registered trademark of Dallas Semiconductor.