AutoStore鈩?/div>
Nonvolatile Static RAM
Industrial Temperature/Military Screen
FEATURES
鈥?Industrial Temperature with Military Screening
鈥?25, 35 and 45ns Access Times
鈥?15 mA I
CC
at 200ns Access Speed
鈥?Automatic
STORE
to
EEPROM
on Power Down
鈥?Hardware or Software initiated
STORE
to
EEPROM
DESCRIPTION
The Simtek STK12C68-IM is a fast static
RAM
(25, 35
and 45ns), with a nonvolatile
EEPROM
element incor-
porated in each static memory cell. The
SRAM
can be
read and written an unlimited number of times, while
independent nonvolatile data resides in
EEPROM
. Data
transfers from the
SRAM
to the
EEPROM
(
the
STORE
operation
) take place automatically upon power down
using charge stored in an external 100
碌F
capacitor.
Transfers from the
EEPROM
to the
SRAM
(the
RECALL
operation) take place automatically on power up. Soft-
ware sequences may also be used to initiate both
STORE
and
RECALL
operations. A
STORE
can also be
initiated via a single pin.
The STK12C68-IM is available in the following
packages: a 28-pin 300 mil ceramic DIP and a 28-pad
LCC. MIL-STD-883 and Standard Military Drawing
(SMD 5962-94599) devices are also available.
鈥?Automatic
STORE
Timing
鈥?100,000
STORE
cycles to
EEPROM
鈥?10 year data retention in
EEPROM
鈥?Automatic
RECALL
on Power Up
鈥?Software initiated
RECALL
from
EEPROM
鈥?Unlimited
RECALL
cycles from
EEPROM
鈥?Single 5V
鹵
10% Operation
鈥?Commercial and Industrial Temperatures
鈥?Available in multiple standard packages
LOGIC BLOCK DIAGRAM
PIN CONFIGURATIONS
V
CAP
V
CAP
V
CCX
A
7
A
12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CCX
W
HSB
A
8
A
9
A
11
G
A
10
E
DQ
7
DQ
6
DQ
5
DQ
4
DQ
3
EEPROM ARRAY
256 x 256
A
3
A
4
ROW DECODER
A
6
A
5
4
5
6
7
8
9
10
11
12
W
A
12
A
7
A
6
HSB
A
8
A
9
A
11
G
A
10
E
DQ
7
DQ
6
3
2
1
28 27
26
25
24
23
STORE
STATIC RAM
ARRAY
256 x 256
A
0
A
12
A
4
A
3
A
2
A
1
A
0
DQ
0
DQ
1
A
5
A
4
A
3
A
2
A
1
A
0
DQ
0
DQ
1
DQ
2
V
SS
A
5
A
6
A
7
A
8
A
9
A
12
DQ
0
DQ
1
DQ
2
DQ
3
DQ
4
DQ
5
DQ
6
DQ
7
RECALL
TOP VIEW
22
21
20
19
18
13 14 15 16 17
DQ
2
DQ
3
DQ
4
STORE/
RECALL
CONTROL
HSB
28 - LCC
DQ
5
Vss
28 - 300 CDIP
COLUMN I/O
PIN NAMES
A
0
- A
12
Address Inputs
Write Enable
Data In/Out
Chip Enable
Output Enable
Power (+5V)
Ground
Capacitor
Hardware Store/Busy
W
DQ
0
- DQ
7
E
INPUT BUFFERS
COLUMN DECODER
A
0
A
1
A
2
A
10
A
11
G
G
V
CCX
V
SS
E
W
V
CAP
HSB
41