DS1251 Datasheet, PDF (1/22 Pages) Dallas Semiconductor – 4096k NV SRAM with Phantom Clock

DS1251/DS1251P
4096k NV SRAM with Phantom Clock
www.maxim-ic.com
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
A18/RST 1
A16 ₂
A14 3
A12 4
A7 5
A6 6
A5 7
A4 8
A3 9
A2 10
A1 11
A0 ¹²
DQ0 ¹³
DQ1 14
DQ2 15
GND 16
32
VCC
31 A15
30 A17
29 WE
28
A13
27 A8
26
A9
25 A11
24
OE
23 A10
22
CE
21 DQ7
20 DQ6
19 DQ5
18 DQ4
17 DQ3
32-Pin Encapsulated Package
740mil Flush
RST ¹
34
A18
A15 ²
33
A17
A16 ³
NC ⁴
VCC
WE
5
6
OE ⁷
CE
DQ7
8
9
32
A14
31
A13
30
A12
29
A11
28
A10
27
A9
26
A8
DQ6 ¹⁰
25
A7
DQ5 ¹¹
DQ4 12
24
A6
23
A5
DQ3 ¹³
22
A4
DQ2
DQ1
DQ0
14
21
15
16
X1 GND VBAT X2
20
19
A3
A2
A1
GND ¹⁷
18
A0
34-Pin PowerCap Module Board
(Uses DS9034PCX PowerCap)
PowerCap is a registered trademark of Dallas Semiconductor.
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