Datasheet

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FEATURES
 10 years minimum data retention in the
absence of external power
 Data is automatically protected during power
loss
 Unlimited write cycles
 Low-power CMOS operation
 Read and write access times of 70 ns
 Lithium energy source is electrically
disconnected to retain freshness until power is
applied for the first time
 Full ± 10% V
CC
operating range (DS1249Y)
 Optional ± 5% V
CC
operating range
(DS1249AB)
 Optional industrial temperature range of
-40°C to +85°C, designated IND
 JEDEC standard 32-pin DIP package
PIN ASSIGNMENT
PIN DESCRIPTION
A0 - A17 - Address Inputs
DQ0 - DQ7 - Data In/Data Out
CE
- Chip Enable
WE
- Write Enable
OE
- Output Enable
V
CC
- Power (+5V)
GND - Ground
NC - No Connect
DESCRIPTION
The DS1249 2048k Nonvolatile SRAMs are 2,097,152-bit, fully static, nonvolatile SRAMs organized as
262,144 words by 8 bits. Each NV SRAM has a self-contained lithium energy source and control circuitry
which constantly monitors V
CC
for an out-of-tolerance condition. When such a condition occurs, the
lithium energy source is automatically switched on and write protection is unconditionally enabled to
prevent data corruption. There is no limit on the number of write cycles which can be executed and no
additional support circuitry is required for microprocessor interfacing.
DS1249Y/AB
2048k Nonvolatile SRAM
19-5631; Rev 11/10
www.maxim-ic.com
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31
32-Pin ENCAPSULATED PACKAGE
740-mil EXTENDED
A14
A7
A5
A4
A3
A2
A1
A0
DQ1
DQ0
V
CC
A15
A17
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ5
DQ6
32
30
29
28
27
26
25
24
23
22
21
19
20
A16
A12
A6
NC
DQ2
GND
15
16
18
17
DQ4
DQ3