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Número de pieza | STK11C88 | |
Descripción | 256 Kbit (32 K x 8) SoftStore nvSRAM | |
Fabricantes | Cypress Semiconductor | |
Logotipo | ||
Hay una vista previa y un enlace de descarga de STK11C88 (archivo pdf) en la parte inferior de esta página. Total 17 Páginas | ||
No Preview Available ! STK11C88
256 Kbit (32 K x 8) SoftStore nvSRAM
Features
■ 25 ns and 45 ns Access Times
■ Pin Compatible with Industry Standard SRAMs
■ Software initiated STORE and RECALL
■ Automatic RECALL to SRAM on Power Up
■ Unlimited Read and Write endurance
■ Unlimited RECALL Cycles
■ 1,000,000 STORE Cycles
■ 100 year Data Retention
■ Single 5 V+10% Power Supply
■ Commercial and Industrial Temperatures
■ 28-pin (300 mil and 330 mil) SOIC packages
■ RoHS compliance
Functional Description
The Cypress STK11C88 is a 256 Kb fast static RAM with a
nonvolatile element in each memory cell. The embedded
nonvolatile elements incorporate QuantumTrap technology
producing the world’s most reliable nonvolatile memory. The
SRAM provides unlimited read and write cycles, while
independent, nonvolatile data resides in the highly reliable
QuantumTrap cell. Data transfers under Software control from
SRAM to the nonvolatile elements (the STORE operation). On
power up, data is automatically restored to the SRAM (the
RECALL operation) from the nonvolatile memory. RECALL
operations are also available under software control.
For a complete list of related documentation, click here.
Logic Block Diagram
Cypress Semiconductor Corporation • 198 Champion Court
Document Number: 001-50591 Rev. *F
• San Jose, CA 95134-1709 • 408-943-2600
Revised March 20, 2015
1 page STK11C88
Hardware Protect
The STK11C88 offers hardware protection against inadvertent
STORE operation and SRAM WRITEs during low voltage condi-
tions. When VCC<VSWITCH, all externally initiated STORE opera-
tions and SRAM WRITEs are inhibited.
Noise Considerations
The STK11C88 is a high speed memory. It must have a high
frequency bypass capacitor of approximately 0.1 µF connected
between VCC and VSS, using leads and traces that are as short
as possible. As with all high speed CMOS ICs, careful routing of
power, ground, and signals help prevent noise problems.
Low Average Active Power
CMOS technology provides the STK11C88 the benefit of
drawing significantly less current when it is cycled at times longer
than 50 ns. Figure 2 and Figure 3 show the relationship between
ICC and READ or WRITE cycle time. Worst case current
consumption is shown for both CMOS and TTL input levels
(commercial temperature range, VCC = 5.5V, 100 percent duty
cycle on chip enable). Only standby current is drawn when the
chip is disabled. The overall average current drawn by the
STK11C88 depends on the following items:
1. The duty cycle of chip enable
2. The overall cycle rate for accesses
3. The ratio of READs to WRITEs
4. CMOS versus TTL input levels
5. The operating temperature
6. The VCC level
7. I/O loading
Figure 2. Icc (max) Reads
Figure 3. Icc (max) Writes
Best Practices
nvSRAM products have been used effectively for over 15 years.
While ease-of-use is one of the product’s main system values,
the experience gained working with hundreds of applications has
resulted in the following suggestions as best practices:
■ The nonvolatile cells in a nvSRAM are programmed on the test
floor during final test and quality assurance. Incoming
inspection routines at customer or contract manufacturer’s
sites, sometimes, reprogram these values. Final NV patterns
are typically repeating patterns of AA, 55, 00, FF, A5, or 5A.
The end product’s firmware should not assume that a NV array
is in a set programmed state. Routines that check memory
content values to determine first time system configuration and
cold or warm boot status, should always program a unique NV
pattern (for example, a complex 4-byte pattern of 46 E6 49 53
hex or more random bytes) as part of the final system manufac-
turing test to ensure these system routines work consistently.
■ Power up boot firmware routines should rewrite the nvSRAM
into the desired state. While the nvSRAM is shipped in a preset
state, best practice is to again rewrite the nvSRAM into the
desired state as a safeguard against events that might flip the
bit inadvertently (program bugs or incoming inspection
routines).
Document Number: 001-50591 Rev. *F
Page 5 of 17
5 Page STK11C88
STORE INHIBIT or Power Up RECALL
Parameter
Alt
tHRECALL [10]
tSTORE [6]
VRESET
VSWITCH
tRESTORE
tHLHZ
Switching Waveforms
Description
Power up RECALL Duration
STORE Cycle Duration
Low Voltage Reset Level
Low Voltage Trigger Level
Figure 9. STORE INHIBIT/Power Up RECALL
STK11C88
Min Max
550
10
3.6
4.0 4.5
VCC
5V
VSWITCH
VRESET
Unit
s
ms
V
V
STORE INHIBIT
POWER-UP RECALL
DQ (DATA OUT)
tHRECALL
POWER-UP
RECALL
BROWN OUT
STORE INHIBIT
NO RECALL
(VCC DID NOT GO
BELOW VRESET)
BROWN OUT
STORE INHIBIT
NO RECALL
(VCC DID NOT GO
BELOW VRESET)
BROWN OUT
STORE INHIBIT
RECALL WHEN
VCC RETURNS
ABOVE VSWITCH
Note
10. tHRECALL starts from the time VCC rises above VSWITCH.
Document Number: 001-50591 Rev. *F
Page 11 of 17
11 Page |
Páginas | Total 17 Páginas | |
PDF Descargar | [ Datasheet STK11C88.PDF ] |
Número de pieza | Descripción | Fabricantes |
STK11C88 | 256 Kbit (32 K x 8) SoftStore nvSRAM | Cypress Semiconductor |
STK11C88 | 32Kx8 SoftStore nvSRAM | Simtek |
STK11C88-3 | 32K X 8 NVSRAM 3.3 V QUANTUM TRAP CMOS NONVOLATILE STATIC RAM | Simtek |
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