Rainbow Electronics DS1258Y_AB User Manual
Rainbow Electronics Storage
E
Copyright 1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
patents and other intellectual property rights, please refer to
Dallas Semiconductor data books.
DS1258Y/AB
128K x 16 Nonvolatile SRAM
DS1258Y/AB
PRODUCT PREVIEW
100395 1/9
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 70 ns
•
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
40–PIN ENCAPSULATED PACKAGE
740 MIL EXTENDED
OE
CEU
CEL
WE
V
CC
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
A16
DQ15
DQ14
DQ13
DQ11
DQ10
DQ9
DQ8
GND
DQ7
DQ5
DQ4
22
21
DQ12
DQ3
DQ2
DQ1
DQ0
DQ6
A15
A14
A13
A12
A11
A10
A9
A8
A7
A6
A5
A4
A3
A2
A1
A0
GND
PIN DESCRIPTION
A0–A16
– Address Inputs
DQ0–DQ15
– Data In/Data Out
CEU
– Chip Enable Upper Byte
CEL
– Chip Enable Lower Byte
WE
– Write Enable
OE
– Output Enable
V
CC
– Power Supply (+5V)
GND
– Ground
DESCRIPTION
The DS1258 128K x 16 Nonvolatile SRAMs are
2,097,152 bit fully static, nonvolatile SRAMs, organized
as 131,072 words by 16 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. DIP–package DS1258 devices can be used
in place of solutions which build nonvolatile 128K x 16
memory by utilizing a variety of discrete components.
There is no limit to the number of write cycles which the
DS12658Y/AB can accept, and no additional support
circuitry is required for microprocessor interfacing.