DS1249Y/AB
2048k Nonvolatile SRAM
www.maxim-ic.com
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 as fast as 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
NC
A16
A14
A12
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
GND
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
V
CC
A15
A17
WE
A13
A8
A9
A11
OE
A10
CE
DQ7
DQ6
DQ5
DQ4
DQ3
32-Pin ENCAPSULATED PACKAGE
740-mil EXTENDED
PIN DESCRIPTION
A0 - A17
DQ0 - DQ7
CE
WE
OE
V
CC
GND
NC
- Address Inputs
- Data In/Data Out
- Chip Enable
- Write Enable
- Output Enable
- Power (+5V)
- Ground
- 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.
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DALLAS [ DALLAS SEMICONDUCTOR ]
