鈥?/div>
RECALL
to SRAM Initiated by Software or
Power Restore
鈥?10mA Typical I
CC
at 200ns Cycle Time
鈥?Unlimited READ, WRITE and
RECALL
Cycles
鈥?1,000,000
STORE
Cycles to EEPROM
鈥?100-Year Data Retention over Full Industrial
Temperature Range
鈥?Commercial and Industrial Temperatures
鈥?28-Pin DIP and SOIC Packages
DESCRIPTION
The Simtek STK11C68 is a fast static
RAM
with a
nonvolatile, electrically erasable
PROM
element
incorporated in each static memory cell. The
SRAM
can be read and written an unlimited number of
times, while independent nonvolatile data resides in
the
EEPROM
. Data transfers from the
SRAM
to the
EEPROM
(the
STORE
operation), or from
EEPROM
to
SRAM
(the
RECALL
operation), take place using a
software sequence. Transfers from the
EEPROM
to
the
SRAM
(the
RECALL
operation) also take place
automatically on restoration of power.
The STK11C68 is pin-compatible with industry-
standard
SRAM
s. MIL-STD-883 device is also
available (STK11C68-M).
BLOCK DIAGRAM
EEPROM ARRAY
128 x 512
PIN CONFIGURATIONS
NC
A
12
A
7
A
6
A
5
A
4
A
3
A
2
A
1
A
0
DQ
0
DQ
1
DQ
2
V
SS
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
A
5
ROW DECODER
A
6
A
7
A
8
A
9
A
11
A
12
DQ
0
DQ
1
DQ
2
DQ
3
DQ
4
DQ
5
DQ
6
DQ
7
STORE
STATIC RAM
ARRAY
128 x 512
RECALL
STORE/
RECALL
CONTROL
SOFTWARE
DETECT
INPUT BUFFERS
COLUMN I/O
COLUMN DEC
A
0
- A
12
V
CC
W
NC
A
8
A
9
A
11
G
A
10
E
DQ
7
DQ
6
DQ
5
DQ
4
DQ
3
28 - 300 PDIP
28 - 300 CDIP
28 - 350 SOIC
PIN NAMES
A
0
- A
12
Address Inputs
Write Enable
Data In/Out
Chip Enable
Output Enable
Power (+ 5V)
Ground
W
A
0
A
1
A
2
A
3
A
4
A
10
G
E
W
DQ
0
- DQ
7
E
G
V
CC
V
SS
June 1999
4-21