41
STK12C68-IM
PIN NAMES
A0 - A12
Address Inputs
W
Write Enable
DQ0 - DQ7
Data In/Out
E
Chip Enable
G
Output Enable
VCCX
Power (+5V)
VSS
Ground
VCAP
Capacitor
HSB
Hardware Store/Busy
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
A
A
A
A
A
A
A
A
DQ
DQ
DQ
DQ
DQ
DQ
DQ
DQ
V
V
W
HSB
A
A
A
G
A
E
SS
7
6
5
4
3
2
1
0
0
1
2
8
9
10
7
6
5
4
3
CAP
A 12
11
CCX
A
A
A
A
A
A
A
A
A
A
DQ
DQ
DQ
G
A
E
DQ
HSB
6
5
4
3
2
1
0
0
1
8
9
11
10
7
6
TOP VIEW
4
5
6
7
8
9
10
11
12
32
1
28 27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
28 - LCC
28 - 300 CDIP
PIN CONFIGURATIONS
A
A
A
A
A
A
4
5
6
7
8
EEPROM ARRAY
256 x 256
STORE
RECALL
STATIC RAM
ARRAY
256 x 256
STORE/
RECALL
CONTROL
AA
A
A
A
0
12
10
12
DQ
DQ
DQ
DQ
DQ
DQ
DQ
DQ
0
1
2
3
4
5
6
7
G
E
W
COLUMN I/O
COLUMN DECODER
AA
011
A3
A
9
12
HSB
LOGIC BLOCK DIAGRAM
STK12C68-IM
CMOS nvSRAM
8K x 8
AutoStore™
Nonvolatile Static RAM
Industrial Temperature/Military Screen
FEATURES
• Industrial Temperature with Military Screening
• 25, 35 and 45ns Access Times
• 15 mA ICC at 200ns Access Speed
• Automatic STORE to EEPROM on Power Down
• Hardware or Software initiated STORE to
EEPROM
• 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
• Commercial and Industrial Temperatures
• Available in multiple standard packages
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
µF 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.