STK17T88
32K x 8 AutoStore™ nvSRAM with
Real Time Clock
Cypress Semiconductor Corporation
•
198 Champion Court
•
San Jose
,
CA 95134-1709
• 408-943-2600
Document Number: 001-52040 Rev. *A
Revised March 17, 2009
Features
■
nvSRAM Combined With Integrated Real-Time Clock
Functions (RTC, Watchdog Timer, Clock Alarm, Power
Monitor)
■
Capacitor or Battery Backup for RTC
■
25, 45 ns Read Access and R/W Cycle Time
■
Unlimited Read/Write Endurance
■
Automatic Nonvolatile STORE on Power Loss
■
Nonvolatile STORE Under Hardware or Software Control
■
Automatic RECALL to SRAM on Power Up
■
Unlimited RECALL Cycles
■
200K STORE Cycles
■
20-Year Nonvolatile Data Retention
■
Single 3V +20%, -10% Power Supply
■
Commercial and Industrial Temperatures
■
48-pin 300-mil SSOP Package (RoHS-Compliant)
Description
The Cypress STK17T88 combines a 256 Kb nonvolatile static
RAM (nvSRAM) with a full-featured real-time clock in a reliable,
monolithic integrated circuit.
The 256 Kb nvSRAM is a fast static RAM with a nonvolatile
Quantum Trap storage element included with each memory cell.
The SRAM provides the fast access and cycle times, ease of use
and unlimited read and write endurance of a normal SRAM. Data
transfers automatically to the nonvolatile storage cells when
power loss is detected (the
STORE
operation). On power up,
data is automatically restored to the SRAM (the
RECALL
operation). Both STORE and RECALL operations are also
available under software control.
The real time clock function provides an accurate clock with leap
year tracking and a programmable, high accuracy oscillator. The
Alarm function is programmable for one-time alarms or periodic
minutes, hours, or days alarms. There is also a programmable
watchdog timer for processor control.
ROW
D
E
CO
DER
IN
PU
T BU
FFER
S
COLUMN DEC
G
E
W
COLUMN I/O
POWER
CONTROL
HSB
STORE/
RECALL
CONTROL
SOFTWARE
DETECT
A
13
– A
0
STORE
RECALL
DQ
0
DQ
1
DQ
2
DQ
3
DQ
4
DQ
5
DQ
6
DQ
7
V
CC
V
CAP
RTC
MUX
A
14
– A
0
X
1
X
2
INT
V
RTCbat
V
RTCcap
A
5
A
6
A
7
A
8
A
9
A
11
A
12
A
13
A
14
A
0
A
1
A
2
A
3
A
4
A
10
Quantum Trap
512 X 512
STATIC RAM
ARRAY
512 X 512
Logic Block Diagram
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