STK22C48
2K x 8 AutoStore™ nvSRAM
QuantumTrap™ CMOS
Nonvolatile Static RAM
FEATURES
DESCRIPTION
The Simtek STK22C48 is a fast static RAM with a
• 25ns, 35ns and 45ns Access Times
• “Hands-off” Automatic STORE with External
nonvolatile element incorporated in each static
memory cell. The SRAM can be read and written an
unlimited number of times, while independent, non-
volatile data resides in Nonvolatile Elements. Data
transfers from the SRAM to the Nonvolatile Elements
(the STORE operation) can take place automatically
on power down. A 68µF or larger capacitor tied from
VCAP to ground guarantees the STORE operation,
regardless of power-down slew rate or loss of power
from “hot swapping”. Transfers from the Nonvolatile
Elements to the SRAM (the RECALL operation) take
place automatically on restoration of power. A hard-
ware STORE may be initiated with the HSB pin.
68µF Capacitor on Power Down
• STORE to Nonvolatile Elements Initiated by
Hardware or AutoStore™ on Power Down
• Automatic RECALL on Power Up
• 10mA Typical ICC at 200ns Cycle Time
• Unlimited READ, WRITE and RECALL Cycles
• 1,000,000 STORE Cycles to Nonvolatile Ele-
ments
• 100-Year Data Retention in Nonvolatile Ele-
ments
• Single 5V + 10% Operation
• Commercial and Industrial Temperatures
• 28-Pin DIP and SOIC Packages
BLOCK DIAGRAM
PIN CONFIGURATIONS
V
V
CAP
CCX
V
1
28
27
26
25
24
23
22
21
20
19
18
17
16
15
V
CAP
NC
CCX
2
3
4
5
6
7
8
9
10
11
12
13
14
W
A
A
A
A
A
HSB
7
6
5
4
3
2
A
8
POWER
Quantum Trap
32 x 512
A
9
CONTROL
NC
G
A
A
E
10
A5
A6
A7
A8
A9
STORE
STORE/
RECALL
A
1
0
HSB
A
DQ
DQ
DQ
DQ
DQ
7
6
5
4
3
STATIC RAM
CONTROL
28 - 300 PDIP
28 - 600 PDIP
28 - 300 SOIC
28 - 350 SOIC
RECALL
DQ
0
1
2
ARRAY
DQ
32 x 512
DQ
V
SS
PIN NAMES
DQ
DQ
DQ
0
1
2
COLUMN I/O
A
- A
Address Inputs
Data In/Out
0
10
COLUMN DEC
DQ -DQ
0
7
DQ
3
4
E
Chip Enable
DQ
W
G
HSB
Write Enable
Output Enable
Hardware Store Busy (I/O)
Power (+ 5V)
Capacitor
DQ
DQ
DQ
5
6
7
A
A A
A A
1 4
2 3
A
10
0
G
E
W
V
V
V
CCX
CAP
SS
Ground
December 2002
1
Document Control # ML0004 rev 0.0