CYPRESS STK12C68

STK12C68
64 Kbit (8K x 8) AutoStore nvSRAM
Features
Functional Description
25 ns, 35 ns, and 45 ns access times
■
Hands off automatic STORE on power down with external 68
µF capacitor
■
STORE to QuantumTrap nonvolatile elements is initiated by
software, hardware, or AutoStore on power down
■
RECALL to SRAM initiated by software or power up
■
Unlimited Read, Write, and Recall cycles
■
1,000,000 STORE cycles to QuantumTrap
■
100 year data retention to QuantumTrap
■
Single 5V+10% operation
■
Commercial and industrial temperatures
■
228-pin (330mil) SOIC, 28-pin (300mil) PDIP, 28-pin (600mil)
PDIP packages
■
28-pin (300 mil) CDIP and 28-pad (350 mil) LCC packages
■
RoHS compliance
The Cypress STK12C68 is a 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 from the SRAM to the nonvolatile elements (the
STORE operation) takes place automatically at power down. On
power up, data is restored to the SRAM (the RECALL operation)
from the nonvolatile memory. Both the STORE and RECALL
operations are also available under software control. A hardware
STORE is initiated with the HSB pin.
N
DECODER
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Logic Block Diagram
A7
A8
A9
A 11
A 12
DQ 0
DQ 1
DQ 2
DQ 3
DQ 4
DQ 5
DQ 6
STATIC RAM
ARRAY
128 X 512
VCAP
POWER
CONTROL
STORE
RECALL
STORE/
RECALL
CONTROL
HSB
SOFTWARE
DETECT
A0
- A 12
COLUMN I/O
INPUT BUFFERS
A5
A6
VCC
Quantum Trap
128 X 512
COLUMN DEC
A 0 A 1 A 2 A 3 A 4 A 10
DQ 7
OE
CE
WE
Cypress Semiconductor Corporation
Document Number: 001-51027 Rev. *C
•
198 Champion Court
•
San Jose, CA 95134-1709
•
408-943-2600
Revised March 7, 2011
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STK12C68
Contents
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DC Electrical Characteristics .......................................... 8
Data Retention and Endurance ....................................... 9
Capacitance ...................................................................... 9
Thermal Resistance.......................................................... 9
AC Test Conditions .......................................................... 9
AC Switching Characteristics ....................................... 10
SRAM Read Cycle .................................................... 10
SRAM Write Cycle ..................................................... 12
AutoStore or Power Up RECALL .................................. 14
Software Controlled STORE/RECALL Cycle................ 15
Hardware STORE Cycle ................................................. 16
Switching Waveform ...................................................... 16
Part Numbering Nomenclature ...................................... 17
Ordering Information ...................................................... 17
Package Diagrams .......................................................... 18
Document History Page ................................................. 23
Sales, Solutions, and Legal Information ...................... 24
Worldwide Sales and Design Support ....................... 24
Products .................................................................... 24
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Pin Configurations ........................................................... 3
Pin Definitions .................................................................. 3
Device Operation .............................................................. 4
SRAM Read ....................................................................... 4
SRAM Write ....................................................................... 4
AutoStore Operation ........................................................ 4
AutoStore Inhibit Mode .................................................... 5
Hardware STORE (HSB) Operation................................. 5
Hardware RECALL (Power Up) ........................................ 5
Software STORE ............................................................... 5
Software RECALL............................................................. 6
Data Protection ................................................................. 6
Noise Considerations....................................................... 6
Hardware Protect.............................................................. 6
Low Average Active Power .............................................. 6
Preventing Store............................................................... 6
Best Practices................................................................... 7
Maximum Ratings ............................................................. 8
Operating Range ............................................................... 8
Document Number: 001-51027 Rev. *C
Page 2 of 24
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STK12C68
Pin Configurations
Pin Definitions
Pin Name
Alt
A0–A12
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Figure 1. 28-Pin SOIC/DIP and LLC
I/O Type
Input
DQ0-DQ7
Description
Address Inputs. Used to select one of the 8,192 bytes of the nvSRAM.
Input or Output Bidirectional Data I/O Lines. Used as input or output lines depending on operation.
WE
W
Input
Write Enable Input, Active LOW. When the chip is enabled and WE is LOW, data on the I/O
pins is written to the specific address location.
CE
E
Input
Chip Enable Input, Active LOW. When LOW, selects the chip. When HIGH, deselects the chip.
G
Input
Output Enable, Active LOW. The active LOW OE input enables the data output buffers during
read cycles. Deasserting OE HIGH causes the I/O pins to tristate.
OE
VSS
Ground
Ground for the Device. The device is connected to ground of the system.
VCC
Power Supply Power Supply Inputs to the Device.
HSB
Input or Output Hardware Store Busy (HSB). When LOW, this output indicates a Hardware Store is in progress.
When pulled low external to the chip, it initiates a nonvolatile STORE operation. A weak internal
pull up resistor keeps this pin high if not connected (connection optional).
VCAP
Power Supply AutoStore Capacitor. Supplies power to nvSRAM during power loss to store data from SRAM
to nonvolatile elements.
Document Number: 001-51027 Rev. *C
Page 3 of 24
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STK12C68
Device Operation
The STK12C68 nvSRAM is made up of two functional components paired in the same physical cell. These are an SRAM
memory cell and a nonvolatile QuantumTrap cell. The SRAM
memory cell operates as a standard fast static RAM. Data in the
SRAM is transferred to the nonvolatile cell (the STORE
operation) or from the nonvolatile cell to SRAM (the RECALL
operation). This unique architecture enables the storage and
recall of all cells in parallel. During the STORE and RECALL
operations, SRAM Read and Write operations are inhibited. The
STK12C68 supports unlimited reads and writes similar to a
typical SRAM. In addition, it provides unlimited RECALL operations from the nonvolatile cells and up to one million STORE
operations.
During normal operation, the device draws current from VCC to
charge a capacitor connected to the VCAP pin. This stored
charge is used by the chip to perform a single STORE operation.
If the voltage on the VCC pin drops below VSWITCH, the part
automatically disconnects the VCAP pin from VCC. A STORE
operation is initiated with power provided by the VCAP capacitor.
Figure 2 shows the proper connection of the storage capacitor
(VCAP) for automatic store operation. A charge storage capacitor
between 68 µF and 220 µF (+20%) rated at 6V should be
provided. The voltage on the VCAP pin is driven to 5V by a charge
pump internal to the chip. A pull up is placed on WE to hold it
inactive during power up.
Figure 2. AutoStore Mode
A Write cycle is performed whenever CE and WE are LOW and
HSB is HIGH. The address inputs must be stable prior to entering
the Write cycle and must remain stable until either CE or WE
goes HIGH at the end of the cycle. The data on the common I/O
pins DQ0–7 are written into the memory if it has valid tSD, before
the end of a WE controlled Write or before the end of an CE
controlled Write. Keep OE HIGH during the entire Write cycle to
avoid data bus contention on common I/O lines. If OE is left LOW,
internal circuitry turns off the output buffers tHZWE after WE goes
LOW.
AutoStore Operation
The STK12C68 stores data to nvSRAM using one of three
storage operations:
1. Hardware store activated by HSB
2. Software store activated by an address sequence
3. AutoStore on device power down
AutoStore operation is a unique feature of QuantumTrap
technology and is enabled by default on the STK12C68.
Document Number: 001-51027 Rev. *C
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SRAM Write
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The STK12C68 performs a Read cycle whenever CE and OE are
LOW while WE and HSB are HIGH. The address specified on
pins A0–12 determines the 8,192 data bytes accessed. When the
Read is initiated by an address transition, the outputs are valid
after a delay of tAA (Read cycle 1). If the Read is initiated by CE
or OE, the outputs are valid at tACE or at tDOE, whichever is later
(Read cycle 2). The data outputs repeatedly respond to address
changes within the tAA access time without the need for transitions on any control input pins, and remains valid until another
address change or until CE or OE is brought HIGH, or WE or
HSB is brought LOW.
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SRAM Read
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In system power mode, both VCC and VCAP are connected to the
+5V power supply without the 68 μF capacitor. In this mode, the
AutoStore function of the STK12C68 operates on the stored
system charge as power goes down. The user must, however,
guarantee that VCC does not drop below 3.6V during the 10 ms
STORE cycle.
To reduce unnecessary nonvolatile stores, AutoStore, and
Hardware Store operations are ignored, unless at least one Write
operation has taken place since the most recent STORE or
RECALL cycle. Software initiated STORE cycles are performed
regardless of whether a Write operation has taken place. An
optional pull up resistor is shown connected to HSB. The HSB
signal is monitored by the system to detect if an AutoStore cycle
is in progress.
Page 4 of 24
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STK12C68
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Figure 3. AutoStore Inhibit Mode
+6%
the STK12C68 continues SRAM operations for tDELAY. During
tDELAY, multiple SRAM Read operations take place. If a Write is
in progress when HSB is pulled LOW, it allows a time, tDELAY to
complete. However, any SRAM Write cycles requested after
HSB goes LOW are inhibited until HSB returns HIGH.
During any STORE operation, regardless of how it is initiated,
the STK12C68 continues to drive the HSB pin LOW, releasing it
only when the STORE is complete. After completing the STORE
operation, the STK12C68 remains disabled until the HSB pin
returns HIGH.
If HSB is not used, it is left unconnected.
Hardware RECALL (Power Up)
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During power up or after any low power condition (VCC <
VRESET), an internal RECALL request is latched. When VCC
once again exceeds the sense voltage of VSWITCH, a RECALL
cycle is automatically initiated and takes tHRECALL to complete.
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If the STK12C68 is in a Write state at the end of power up
RECALL, the SRAM data is corrupted. To help avoid this
situation, a 10 Kohm resistor is connected either between WE
and system VCC or between CE and system VCC.
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Software STORE
If the power supply drops faster than 20 us/volt before Vcc
reaches VSWITCH, then a 2.2 ohm resistor should be connected
between VCC and the system supply to avoid momentary excess
of current between VCC and VCAP.
AutoStore Inhibit Mode
If an automatic STORE on power loss is not required, then VCC
is tied to ground and +5V is applied to VCAP (Figure 3). This is
the AutoStore Inhibit mode, where the AutoStore function is
disabled. If the STK12C68 is operated in this configuration, references to VCC are changed to VCAP throughout this data sheet.
In this mode, STORE operations are triggered through software
control or the HSB pin. To enable or disable Autostore using an
I/O port pin see Preventing Store on page 6. It is not permissible
to change between these three options “on the fly”.
Hardware STORE (HSB) Operation
The STK12C68 provides the HSB pin for controlling and
acknowledging the STORE operations. The HSB pin is used to
request a hardware STORE cycle. When the HSB pin is driven
LOW, the STK12C68 conditionally initiates a STORE operation
after tDELAY. An actual STORE cycle only begins if a Write to the
SRAM takes place since the last STORE or RECALL cycle. The
HSB pin also acts as an open drain driver that is internally driven
LOW to indicate a busy condition, while the STORE (initiated by
any means) is in progress.
SRAM Read and Write operations, that are in progress when
HSB is driven LOW by any means, are given time to complete
before the STORE operation is initiated. After HSB goes LOW,
Document Number: 001-51027 Rev. *C
Data is transferred from the SRAM to the nonvolatile memory by
a software address sequence. The STK12C68 software STORE
cycle is initiated by executing sequential CE controlled Read
cycles from six specific address locations in exact order. During
the STORE cycle, an erase of the previous nonvolatile data is
first performed followed by a program of the nonvolatile
elements. When a STORE cycle is initiated, input and output are
disabled until the cycle is completed.
Because a sequence of Reads from specific addresses is used
for STORE initiation, it is important that no other Read or Write
accesses intervene in the sequence. If they intervene, the
sequence is aborted and no STORE or RECALL takes place.
To initiate the software STORE cycle, the following Read
sequence is performed:
1. Read address 0x0000, Valid READ
2. Read address 0x1555, Valid READ
3. Read address 0x0AAA, Valid READ
4. Read address 0x1FFF, Valid READ
5. Read address 0x10F0, Valid READ
6. Read address 0x0F0F, Initiate STORE cycle
The software sequence is clocked with CE controlled Reads or
OE controlled Reads. When the sixth address in the sequence
is entered, the STORE cycle commences and the chip is
disabled. It is important that Read cycles and not Write cycles
are used in the sequence. It is not necessary that OE is LOW for
a valid sequence. After the tSTORE cycle time is fulfilled, the
SRAM is again activated for Read and Write operation.
Page 5 of 24
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STK12C68
Software RECALL
Data is transferred from the nonvolatile memory to the SRAM by
a software address sequence. A software RECALL cycle is
initiated with a sequence of Read operations in a manner similar
to the software STORE initiation. To initiate the RECALL cycle,
the following sequence of CE controlled Read operations is
performed:
1. Read address 0x0000, Valid READ
2. Read address 0x1555, Valid READ
3. Read address 0x0AAA, Valid READ
4. Read address 0x1FFF, Valid READ
5. Read address 0x10F0, Valid READ
6. Read address 0x0F0E, Initiate RECALL cycle
■
The duty cycle of chip enable
■
The overall cycle rate for accesses
■
The ratio of Reads to Writes
■
CMOS versus TTL input levels
■
The operating temperature
■
The VCC level
I/O loading
Figure 4. Current Versus Cycle Time (Read)
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The STK12C68 protects data from corruption during low voltage
conditions by inhibiting all externally initiated STORE and Write
operations. The low voltage condition is detected when VCC is
less than VSWITCH. If the STK12C68 is in a Write mode (both CE
and WE are low) at power up after a RECALL or after a STORE,
the Write is inhibited until a negative transition on CE or WE is
detected. This protects against inadvertent writes during power
up or brown out conditions.
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Data Protection
.
Internally, RECALL is a two step procedure. First, the SRAM data
is cleared; then, the nonvolatile information is transferred into the
SRAM cells. After the tRECALL cycle time, the SRAM is again
ready for Read and Write operations. The RECALL operation
does not alter the data in the nonvolatile elements. The nonvolatile data can be recalled an unlimited number of times.
Figure 5. Current Versus Cycle Time (Write)
Noise Considerations
The STK12C68 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 reduce circuit noise.
Hardware Protect
The STK12C68 offers hardware protection against inadvertent
STORE operation and SRAM Writes during low voltage conditions. When VCAP<VSWITCH, all externally initiated STORE
operations and SRAM Writes are inhibited. AutoStore can be
completely disabled by tying VCC to ground and applying +5V to
VCAP. This is the AutoStore Inhibit mode; in this mode, STOREs
are only initiated by explicit request using either the software
sequence or the HSB pin.
Low Average Active Power
CMOS technology provides the STK12C68 the benefit of
drawing significantly less current when it is cycled at times longer
than 50 ns. Figure 4 shows 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% duty cycle on chip enable). Only
standby current is drawn when the chip is disabled. The overall
average current drawn by the STK12C68 depends on the
following items:
Document Number: 001-51027 Rev. *C
Preventing Store
The STORE function is disabled by holding HSB high with a
driver capable of sourcing 30 mA at a VOH of at least 2.2V,
because it must overpower the internal pull down device. This
device drives HSB LOW for 20 μs at the onset of a STORE.
When the STK12C68 is connected for AutoStore operation
(system VCC connected to VCC and a 68 μF capacitor on VCAP)
and VCC crosses VSWITCH on the way down, the STK12C68
attempts to pull HSB LOW. If HSB does not actually get below
VIL, the part stops trying to pull HSB LOW and abort the STORE
attempt.
Page 6 of 24
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STK12C68
Best Practices
manufacturing test to ensure these system routines work
consistently.
The nonvolatile cells in an nvSRAM are programmed on the
test floor during final test and quality assurance. Incoming
inspection routines at customer or contract manufacturer’s
sites sometimes reprograms 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 an NV array
is in a set programmed state. Routines that check memory
content values to determine first time system configuration,
cold or warm boot status, and so on must always program a
unique NV pattern (for example, complex 4-byte pattern of 46
E6 49 53 hex or more random bytes) as part of the final system
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, incoming inspection routines,
and so on).
■
The Vcap value specified in this data sheet includes a minimum
and a maximum value size. The best practice is to meet this
requirement and not exceed the maximum Vcap value because
the higher inrush currents may reduce the reliability of the
internal pass transistor. Customers who want to use a larger
Vcap value to make sure there is extra store charge should
discuss their Vcap size selection with Cypress.
.
■
■
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nvSRAM products have been used effectively for over 15 years.
While ease-of-use is one of the product’s main system values,
experience gained working with hundreds of applications has
resulted in the following suggestions as best practices:
WE
HSB
A12–A0
Mode
I/O
Power
H
X
H
X
Not Selected
Output High Z
Standby
L
H
H
X
Read SRAM
Output Data
Active[3]
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Table 1. Hardware Mode Selection
L
H
X
Write SRAM
Input Data
Active
X
L
X
Nonvolatile STORE
Output High Z
ICC2[1]
L
H
H
0x0000
0x1555
0x0AAA
0x1FFF
0x10F0
0x0F0F
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile STORE
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
Active ICC2[2, 3]
L
H
H
0x0000
0x1555
0x0AAA
0x1FFF
0x10F0
0x0F0E
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Read SRAM
Nonvolatile RECALL
Output Data
Output Data
Output Data
Output Data
Output Data
Output High Z
Active[2, 3]
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Notes
1. HSB STORE operation occurs only if an SRAM Write is done since the last nonvolatile cycle. After the STORE (If any) completes, the part goes into standby
mode, inhibiting all operations until HSB rises.
2. The six consecutive addresses must be in the order listed. WE must be high during all six consecutive CE controlled cycles to enable a nonvolatile cycle.
3. I/O state assumes OE < VIL. Activation of nonvolatile cycles does not depend on state of OE.
Document Number: 001-51027 Rev. *C
Page 7 of 24
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STK12C68
Maximum Ratings
Voltage on DQ0-7 or HSB .......................–0.5V to Vcc + 0.5V
Exceeding maximum ratings may shorten the useful life of the
device. These user guidelines are not tested.
Storage Temperature ................................. –65°C to +150°C
Power Dissipation.......................................................... 1.0W
DC output Current (1 output at a time, 1s duration) .... 15 mA
Operating Range
Temperature under Bias ............................. –55°C to +125°C
Range
Voltage on Input Relative to GND.....................–0.5V to 7.0V
Commercial
Voltage on Input Relative to Vss............ –0.6V to VCC + 0.5V
Industrial
Ambient Temperature
VCC
0°C to +70°C
4.5V to 5.5V
-40°C to +85°C
4.5V to 5.5V
DC Electrical Characteristics
Over the operating range (VCC = 4.5V to 5.5V) [4]
Parameter
Description
Test Conditions
Min
Max
Unit
85
75
65
mA
mA
mA
3
mA
Average VCC Current
tRC = 25 ns
tRC = 35 ns
tRC = 45 ns
Dependent on output loading and cycle rate. Values obtained
without output loads.
IOUT = 0 mA.
ICC2
Average VCC Current
during STORE
All Inputs Do Not Care, VCC = Max
Average current for duration tSTORE
ICC3
Average VCC Current at WE > (VCC – 0.2V). All other inputs cycling.
tRC= 200 ns, 5V, 25°C Dependent on output loading and cycle rate. Values obtained
without output loads.
Typical
10
mA
ICC4
Average VCAP Current All Inputs Do Not Care, VCC = Max
during AutoStore Cycle Average current for duration tSTORE
2
mA
ISB1[5]
VCC Standby Current
(Standby, Cycling TTL
Input Levels)
tRC = 25 ns, CE > VIH
tRC = 35 ns, CE > VIH
tRC = 45 ns, CE > VIH
27
24
20
mA
mA
mA
ISB2 [5]
VCC Standby Current
CE > (VCC – 0.2V). All others VIN < 0.2V or > Commercial
(VCC – 0.2V). Standby current level after
nonvolatile cycle is complete.
Industrial
Inputs are static. f = 0 MHz.
1.5
mA
2.5
mA
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ICC1
IIX
Input Leakage Current VCC = Max, VSS < VIN < VCC
-1
+1
μA
IIX
Input Leakage Current VCC = Max, VSS < VIN < VCC
-1
+1
μA
IOZ
Off State Output
Leakage Current
-5
+5
μA
VIH
Input HIGH Voltage
2.2
VCC +
0.5
V
VIL
Input LOW Voltage
VSS – 0.5
0.8
V
VOH
Output HIGH Voltage
IOUT = –4 mA
VOL
Output LOW Voltage
IOUT = 8 mA
0.4
V
VBL
Logic ‘0’ Voltage on
HSB Output
IOUT = 3 mA
0.4
V
VCAP
Storage Capacitor
Between Vcap pin and Vss, 6V rated. 68 µF +20% nom.
260
µF
VCC = Max, VSS < VIN < VCC, CE or OE > VIH or WE < VIL
2.4
54
V
Notes
4. VCC reference levels throughout this data sheet refer to VCC if that is where the power supply connection is made, or VCAP if VCC is connected to ground.
5. CE > VIH does not produce standby current levels until any nonvolatile cycle in progress has timed out.
Document Number: 001-51027 Rev. *C
Page 8 of 24
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STK12C68
Data Retention and Endurance
Parameter
Description
DATAR
Data Retention
NVC
Nonvolatile STORE Operations
Min
Unit
100
Years
1,000
K
Capacitance
In the following table, the capacitance parameters are listed.[6]
Parameter
Description
CIN
Input Capacitance
COUT
Output Capacitance
Test Conditions
TA = 25°C, f = 1 MHz,
VCC = 0 to 3.0 V
Max
Unit
8
pF
7
pF
Thermal Resistance
28-PDIP
(300 mil)
28-PDIP
(600 mil)
28-CDIP
28-LCC
Unit
Test conditions follow
standard test methods and
procedures for measuring
thermal impedance, per EIA /
JESD51.
46.55
45.16
55.84
46.1
95.31
°C/W
27.95
31.62
5.01
9.01
°C/W
am
Thermal Resistance
(Junction to Case)
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Thermal Resistance
(Junction to
Ambient)
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ΘJA
on
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28-SOIC
s
Test Conditions
Description
io
Parameter
.
In the following table, the thermal resistance parameters are listed.[6]
25.74
Figure 6. AC Test Loads
R1 963Ω
5.0V
Output
R1 963Ω For Tri-state Specs
5.0V
Output
30 pF
R2
512Ω
5 pF
R2
512Ω
AC Test Conditions
Input Pulse Levels .................................................. 0 V to 3 V
Input Rise and Fall Times (10% to 90%) ...................... <5 ns
Input and Output Timing Reference Levels .......................1.5
Note
6. These parameters are guaranteed by design and are not tested.
Document Number: 001-51027 Rev. *C
Page 9 of 24
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STK12C68
AC Switching Characteristics
SRAM Read Cycle
25 ns
Min
Max
Min
25
45 ns
Max
25
10
45
35
15
5
5
45
20
5
5
5
5
10
0
0
12
.
10
0
10
12
s
10
0
25
Switching Waveforms
Max
45
35
0
Min
35
25
am
Chip Enable Access Time
Read Cycle Time
Address Access Time
Output Enable to Data Valid
Output Hold After Address Change
Chip Enable to Output Active
Chip Disable to Output Inactive
Output Enable to Output Active
Output Disable to Output Inactive
Chip Enable to Power Active
Chip Disable to Power Standby
35 ns
on
ly
Description
pr
og
r
Parameter
Cypress
Alt
Parameter
tELQV
tACE
tAVAV, tELEH
tRC [7]
tAVQV
tAA [8]
tGLQV
tDOE
tAXQX
tOHA [8]
tELQX
tLZCE [9]
tEHQZ
tHZCE [9]
[9]
tGLQX
tLZOE
tGHQZ
tHZOE [9]
tELICCH
tPU [6]
[6]
tEHICCL
tPD
0
35
45
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
N
In ot R
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pr ns.
od
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t
io
n
Figure 7. SRAM Read Cycle 1: Address Controlled [7, 8]
W5&
$''5(66
W $$
W2+$
'4'$7$287
'$7$9$/,'
Figure 8. SRAM Read Cycle 2: CE and OE Controlled [7]
W5&
$''5(66
W$&(
W3'
W/=&(
&(
W+=&(
2(
W+=2(
W'2(
W/=2(
'4'$7$287
'$7$9$/,'
W 38
,&&
$&7,9(
67$1'%<
Document Number: 001-51027 Rev. *C
Page 10 of 24
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STK12C68
Switching Waveforms
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
n
pr
og
r
am
s
on
ly
.
Notes
7. WE and HSB must be High during SRAM Read cycles.
8. Device is continuously selected with CE and OE both Low.
9. Measured ±200 mV from steady state output voltage.
Document Number: 001-51027 Rev. *C
Page 11 of 24
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STK12C68
SRAM Write Cycle
Parameter
tAVAV
tWLWH, tWLEH
tELWH, tELEH
tDVWH, tDVEH
tWHDX, tEHDX
tAVWH, tAVEH
tAVWL, tAVEL
tWHAX, tEHAX
tWLQZ
tWHQX
tWC
tPWE
tSCE
tSD
tHD
tAW
tSA
tHA
tHZWE [9,10]
tLZWE [9]
Min
Write Cycle Time
Write Pulse Width
Chip Enable To End of Write
Data Setup to End of Write
Data Hold After End of Write
Address Setup to End of Write
Address Setup to Start of Write
Address Hold After End of Write
Write Enable to Output Disable
Output Active After End of Write
Max
Min
25
20
20
10
0
20
0
0
35
25
25
12
0
25
0
0
10
5
45 ns
Min
Max
45
30
30
15
0
30
0
0
5
13
14
5
Unit
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
am
s
Switching Waveforms
Max
.
Alt
35 ns
on
ly
Cypress
Parameter
25 ns
Description
pr
og
r
Figure 9. SRAM Write Cycle 1: WE Controlled [11, 12]
tWC
N
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ADDRESS
tHA
tSCE
CE
tAW
tSA
WE
tPWE
tSD
DATA IN
tHD
DATA VALID
tHZWE
DATA OUT
tLZWE
HIGH IMPEDANCE
PREVIOUS DATA
Figure 10. SRAM Write Cycle 2: CE Controlled [11, 12]
tWC
ADDRESS
CE
WE
tHA
tSCE
tSA
tAW
tPWE
tSD
DATA IN
DATA OUT
Document Number: 001-51027 Rev. *C
tHD
DATA VALID
HIGH IMPEDANCE
Page 12 of 24
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STK12C68
Switching Waveforms
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
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oi es
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pr ns.
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s
on
ly
.
Notes
10. If WE is Low when CE goes Low, the outputs remain in the high impedance state.
11. HSB must be high during SRAM Write cycles.
12. CE or WE must be greater than VIH during address transitions.
Document Number: 001-51027 Rev. *C
Page 13 of 24
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STK12C68
AutoStore or Power Up RECALL
Parameter
Alt
tHRECALL [13]
tSTORE [14, 15, 16]
tDELAY [9, 15]
VSWITCH
VRESET
tVCCRISE
tVSBL[11]
tRESTORE
tHLHZ
tHLQZ , tBLQZ
Description
Power up RECALL Duration
STORE Cycle Duration
Time Allowed to Complete SRAM Cycle
Low Voltage Trigger Level
Low Voltage Reset Level
VCC Rise Time
Low Voltage Trigger (VSWITCH) to HSB Low
STK12C68
Min
Max
550
10
1
4.0
4.5
3.9
150
300
Unit
μs
ms
μs
V
V
μs
ns
Switching Waveform
WE
N
In ot R
pr e
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uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
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oi es
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pr ns.
od
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pr
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am
s
on
ly
.
Figure 11. AutoStore/Power Up RECALL
Notes
13. tHRECALL starts from the time VCC rises above VSWITCH.
14. CE and OE low for output behavior.
15. CE and OE low and WE high for output behavior.
16. HSB is asserted low for 1us when VCAP drops through VSWITCH. If an SRAM Write has not taken place since the last nonvolatile cycle, HSB is released and no store
takes place.
Document Number: 001-51027 Rev. *C
Page 14 of 24
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STK12C68
Software Controlled STORE/RECALL Cycle
The software controlled STORE/RECALL cycle follows. [18]
Parameter
Alt
Description
25 ns
Min
35 ns
Max
Min
Max
45 ns
Min
Max
Unit
tRC[14]
tAVAV
STORE/RECALL Initiation Cycle Time
25
35
45
ns
tSA[17]
tCW[17]
tHACE[17]
tAVEL
Address Setup Time
0
0
0
ns
tELEH
Clock Pulse Width
20
25
30
ns
tELAX
Address Hold Time
20
20
20
ns
RECALL Duration
tRECALL
20
20
20
μs
ADDRESS # 1
ADDRESS # 6
tSCE
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
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oi es
ng ig
pr ns.
od
uc
t
tSA
CE
io
n
ADDRESS
tRC
pr
og
r
tRC
am
s
on
ly
Figure 12. CE Controlled Software STORE/RECALL Cycle [18]
.
Switching Waveform
tHACE
OE
DQ (DATA)
DATA VALID
t STORE / t RECALL
DATA VALID
HIGH IMPEDANCE
Notes
17. The software sequence is clocked on the falling edge of CE without involving OE (double clocking aborts the sequence).
18. The six consecutive addresses must be read in the order listed in Table 1 on page 7. WE must be HIGH during all six consecutive cycles.
Document Number: 001-51027 Rev. *C
Page 15 of 24
[+] Feedback
STK12C68
Hardware STORE Cycle
Parameter
tSTORE [9, 14]
tDHSB
tPHSB
[14, 19]
Alt
tHLHZ
STK12C68
Description
Min
STORE Cycle Duration
tRECOVER, tHHQX Hardware STORE High to Inhibit Off
tHLHX
Hardware STORE Pulse Width
tHLBL
Max
10
ms
700
ns
15
Hardware STORE Low to STORE Busy
Unit
ns
300
ns
Switching Waveform
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
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pr
og
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am
s
on
ly
.
Figure 13. Hardware STORE Cycle
Note
19. tDHSB is only applicable after tSTORE is complete.
Document Number: 001-51027 Rev. *C
Page 16 of 24
[+] Feedback
STK12C68
Part Numbering Nomenclature
STK12C68 - S F 45 I TR
Packaging Option:
TR = Tape and Reel
Blank = Tube
Temperature Range:
C - Commercial (0 to 70°C)
I - Industrial (-40 to 85°C)
.
Lead Finish
Speed:
25 - 25 ns
35 - 35 ns
45 - 45 ns
s
on
ly
F = 100% Sn (Matte Tin)
N
In ot R
pr e
od co
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tio e
n nd
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pp or
or Ne
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pr ns.
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Package:
S = Plastic 28-pin 330 mil SOIC
P = Plastic 28-pin 300 mil DIP
W = Plastic 28-pin 600 mil DIP
C = Ceramic 28-pin 300 mil DIP
L = Ceramic 28-pin LLC
Ordering Information
These parts are not recommended for new designs. They are in production to support ongoing production programs only.
Speed (ns)
25
35
45
Ordering Code
STK12C68-SF25TR
Package Diagram
001-85058
Package Type
28-pin SOIC (330 mil)
STK12C68-SF25
001-85058
28-pin SOIC (330 mil)
STK12C68-SF25ITR
001-85058
28-pin SOIC (330 mil)
STK12C68-SF25I
001-85058
28-pin SOIC (330 mil)
STK12C68-PF25I
001-85014
28-pin PDIP (300 mil)
Operating Range
Commercial
Industrial
STK12C68-WF25I
001-85017
28-pin PDIP (600 mil)
STK12C68-C35
001-51695
28-pin CDIP (300 mil)
Commercial
Commercial
STK12C68-SF45TR
001-85058
28-pin SOIC (330 mil)
STK12C68-SF45
001-85058
28-pin SOIC (330 mil)
STK12C68-SF45ITR
001-85058
28-pin SOIC (330 mil)
STK12C68-SF45I
001-85058
28-pin SOIC (330 mil)
STK12C68-C45I
001-51695
28-pin CDIP (300 mil)
Industrial
All parts are Pb-free. The above table contains Final information. Contact your local Cypress sales representative for availability of these parts
Document Number: 001-51027 Rev. *C
Page 17 of 24
[+] Feedback
STK12C68
Package Diagrams
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
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oi es
ng ig
pr ns.
od
uc
t
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pr
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am
s
on
ly
.
Figure 14. 28-Pin (330 Mil) SOIC (51-85058)
Document Number: 001-51027 Rev. *C
51-85058 *B
Page 18 of 24
[+] Feedback
STK12C68
Package Diagrams (continued)
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
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oi es
ng ig
pr ns.
od
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t
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pr
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am
s
on
ly
.
Figure 15. 28-Pin (300 Mil) PDIP (51-85014)
Document Number: 001-51027 Rev. *C
51-85014 *E
Page 19 of 24
[+] Feedback
STK12C68
Package Diagrams (continued)
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
n
pr
og
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am
s
on
ly
.
Figure 16. 28-Pin (600 Mil) PDIP (51-85017)
Document Number: 001-51027 Rev. *C
51-85017 *D
Page 20 of 24
[+] Feedback
STK12C68
Package Diagrams (continued)
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
n
pr
og
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am
s
on
ly
.
Figure 17. 28-Pin (300 Mil) Side Braze DIL (001-51695)
Document Number: 001-51027 Rev. *C
001-51695 *A
Page 21 of 24
[+] Feedback
STK12C68
Package Diagrams (continued)
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
n
pr
og
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am
s
on
ly
.
Figure 18. 28-Pad (350 Mil) LCC (001-51696)
Document Number: 001-51027 Rev. *C
001-51696 *A
Page 22 of 24
[+] Feedback
STK12C68
Document History Page
Document Title: STK12C68 64 Kbit (8K x 8) AutoStore nvSRAM
Document Number: 001-51027
Rev.
ECN No.
Orig. of
Change
Submission
Date
Description of Change
2606744
GVCH
01/30/2009
New data sheet
2826441
GVCH
12/11/2009
Added following text in the Ordering Information section: “These parts are
not recommended for new designs. In production to support ongoing production programs only.”
Added watermark in PDF stating “Not recommended for new designs. In
production to support ongoing production programs only.”
Added Contents on page 2.
*B
3054694
GVCH
10/12/2010
Removed the following prune parts from the document;
STK12C68-C35I
STK12C68-C45
STK12C68-L35
STK12C68-L35I
STK12C68-L45
STK12C68-L45I
STK12C68-PF25
STK12C68-PF45
STK12C68-PF45I
STK12C68-WF45
STK12C68-WF45I
STK12C68-WF25
*C
3189527
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
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pr
og
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am
s
on
ly
.
**
*A
GVCH
Document Number: 001-51027 Rev. *C
03/07/2011
Added watermark in PDF stating “Not recommended for new designs. In
production to support ongoing production programs only.”
Page 23 of 24
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STK12C68
Sales, Solutions, and Legal Information
Worldwide Sales and Design Support
Cypress maintains a worldwide network of offices, solution centers, manufacturer’s representatives, and distributors. To find the office
closest to you, visit us at cypress.com/sales.
Products
Automotive
Clocks & Buffers
Interface
Lighting & Power Control
PSoC Solutions
cypress.com/go/automotive
psoc.cypress.com/solutions
cypress.com/go/clocks
PSoC 1 | PSoC 3 | PSoC 5
cypress.com/go/interface
cypress.com/go/powerpsoc
cypress.com/go/plc
Touch Sensing
USB Controllers
.
on
ly
cypress.com/go/psoc
cypress.com/go/touch
cypress.com/go/USB
cypress.com/go/wireless
N
In ot R
pr e
od co
uc mm
tio e
n nd
to e
su d f
pp or
or Ne
to w
ng D
oi es
ng ig
pr ns.
od
uc
t
io
n
Wireless/RF
cypress.com/go/image
s
PSoC
am
Optical & Image Sensing
cypress.com/go/memory
pr
og
r
Memory
© Cypress Semiconductor Corporation, 2009-2011. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of
any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for
medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as
critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems
application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign),
United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of,
and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in conjunction with a Cypress
integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as specified above is prohibited without
the express written permission of Cypress.
Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not
assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where
a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer
assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
Document Number: 001-51027 Rev. *C
Revised March 7, 2011
Page 24 of 24
All products and company names mentioned in this document may be the trademarks of their respective holders.
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