December 2002
1
Document Control # ML0004 rev 0.0
PIN CONFIGURATIONS
VCAP
NC
A7
A6
A5
A4
A3
A2
A1
A0
DQ0
DQ1
DQ2
VSS
VCCX
HSB
A8
A9
NC
G
W
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
A10
E
DQ7
DQ6
DQ5
DQ4
DQ3
28 - 300 PDIP
28 - 600 PDIP
28 - 300 SOIC
28 - 350 SOIC
PIN NAMES
A0 - A10
Address Inputs
DQ0 -DQ7
Data In/Out
E
Chip Enable
W
Write Enable
G
Output Enable
HSB
Hardware Store Busy (I/O)
VCCX
Power (+ 5V)
VCAP
Capacitor
VSS
Ground
STK22C48
2K x 8 AutoStore™nvSRAM
QuantumTrap™ CMOS
Nonvolatile Static RAM
FEATURES
• 25ns, 35ns and 45ns Access Times
• “Hands-off” Automatic STORE with External
68
µF Capacitor on Power Down
• STORE to Nonvolatile Elements Initiated by
Hardware or AutoStore™ on Power Down
•Automatic RECALL on Power Up
• 10mA Typical I
CC 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
DESCRIPTION
The Simtek STK22C48 is a fast static RAM with a
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 68
µF or larger capacitor tied from
V
CAP 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.
BLOCK DIAGRAM
COLUMN I/O
COLUMN DEC
STATIC RAM
ARRAY
32 x 512
Quantum Trap
32 x 512
STORE/
RECALL
CONTROL
STORE
RECALL
POWER
CONTROL
A5
A6
A9
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
G
E
W
A8
A7
A10
A3
A2
A0 A1
A4
VCCX
VCAP
HSB