DS1258Y/AB
128k x 16 Nonvolatile SRAM
www.maxim-ic.com
FEATURES
§
§
§
§
§
§
§
§
§
§
10-Year Minimum Data Retention in the
Absence of External Power
Data is Automatically Protected During a
Power Loss
Separate Upper Byte and Lower Byte Chip-
Select Inputs
Unlimited Write Cycles
Low-Power CMOS
Read and Write Access Times as Fast as 70ns
Lithium Energy Source is Electrically
Disconnected to Retain Freshness Until
Power is Applied for the First Time
Full
±10%
Operating Range (DS1258Y)
Optional
±5%
Operating Range (DS1258AB)
Optional Industrial Temperature Range of
-40°C to +85°C, Designated IND
PIN ASSIGNMENT
CEU
CEL
DQ15
DQ14
DQ13
DQ12
DQ11
DQ10
DQ9
DQ8
GND
DQ7
DQ6
DQ5
DQ4
DQ3
DQ2
DQ1
DQ0
OE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
V
CC
WE
A16
A15
A14
A13
A12
A11
A10
A9
GND
A8
A7
A6
A5
A4
A3
A2
A1
A0
40-Pin Encapsulated Package
740mil Extended
PIN DESCRIPTION
A0 to A16
DQ0 to DQ15
CEU
CEL
WE
OE
V
CC
GND
- Address Inputs
- Data In/Data Out
- Chip Enable Upper Byte
- Chip Enable Lower Byte
- Write Enable
- Output Enable
- Power (+5V)
- Ground
DESCRIPTION
The DS1258 128k x 16 nonvolatile (NV) SRAMs are 2,097,152-bit fully static, NV SRAMs, organized as
131,072 words by 16 bits. Each NV SRAM has a self-contained lithium energy source and control
circuitry that 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. DIP-package DS1258 devices can be used in place of solutions that build NV
128k x 16 memory by utilizing a variety of discrete components. There is no limit on the number of write
cycles that can be executed and no additional support circuitry is required for microprocessor interfacing.
1 of 8
033104
DALLAS [ DALLAS SEMICONDUCTOR ]
