STK12C68-M
STK12C68-M
CMOS nvSRAM
8K x 8 AutoStore™
Nonvolatile Static RAM
MIL-STD-883 / SMD # 5962-94599
DESCRIPTION
FEATURES
The Simtek STK12C68-M is a fast static RAM (40, 45
and 55ns), with a nonvolatile EEPROM element incor-
porated in each static memory cell. The SRAM can be
• 40, 45 and 55ns Access Times
• 15 mA I at 200ns Access Speed
CC
• Automatic STORE to EEPROM on Power Down
• Hardware or Software initiated STORE to
EEPROM
read and written an unlimited number of times, while
independent nonvolatile data resides in EEPROM.
Data transfers from the SRAM to the EEPROM (the
STOREoperation)takeplaceautomaticallyuponpower
down using charge stored in an external 100 µF
capacitor. Transfers from the EEPROM to the SRAM
(the RECALL operation) take place automatically on
power up. Software sequences may also be used to
• Automatic STORE Timing
• 100,000 STORE cycles to EEPROM
• 10 year data retention in EEPROM
• Automatic RECALL on Power Up
• Software initiated RECALL from EEPROM
• Unlimited RECALL cycles from EEPROM
• Single 5V±10% Operation
initiate both STORE and RECALL operations.
STORE can also be initiated via a single pin.
A
The STK12C68-M is available in the following pack-
ages: a 28-pin 300 mil ceramic DIP and 28-pad LCC.
• Available in multiple standard packages
LOGIC BLOCK DIAGRAM
PIN CONFIGURATIONS
1
V
28
V
CCX
CAP
EEPROM ARRAY
256 x 256
2
3
27
26
W
A
A
A
A
A
A
12
HSB
7
3
2
28 27
26
A3
25
24
1
4
5
A
A
A
G
8
9
6
4
5
A
A
HSB
6
5
4
STORE
5
25
24
23
22
21
A
A
A
8
9
A4
23
22
6
7
6
4
11
A
A
A
A
A5
7
RECALL
STATIC RAM
3
3
2
1
0
11
8
9
21
20
8
A
A
A
E
G
A
E
10
TOP VIEW
2
1
0
0
A6
ARRAY
9
10
A7
10
11
19
18
10
A
DQ
DQ
DQ
DQ
DQ
7
6
20
19
18
A
DQ
DQ
A 0
A12
256 x 256
11
12
DQ
DQ
DQ
0
1
7
6
A8
A9
17
16
15
12
13
14
DQ
DQ
V
5
4
1
2
13 14 15 16 17
HSB
STORE/
RECALL
CONTROL
3
SS
A
12
28 - 300 C-DIP
28 - LCC
DQ0
COLUMN I/O
DQ1
DQ2
DQ3
PIN NAMES
A
- A
12
Address Inputs
0
COLUMN DECODER
W
Write Enable
Data In/Out
DQ - DQ
0
7
DQ4
DQ5
E
Chip Enable
Output Enable
Power (+5V)
Ground
A0
A1
A2
A
A11
10
G
E
G
DQ6
DQ7
V
CCX
V
SS
V
Capacitor
CAP
W
Hardware Store/Busy
HSB
4-53