STK14C88-NF45 Cypress Semiconductor Corp, STK14C88-NF45 Datasheet - Page 5
![IC NVSRAM 256KBIT 45NS 32SOIC](/photos/31/34/313454/42832soic_sml.jpg)
STK14C88-NF45
Manufacturer Part Number
STK14C88-NF45
Description
IC NVSRAM 256KBIT 45NS 32SOIC
Manufacturer
Cypress Semiconductor Corp
Type
NVSRAMr
Specifications of STK14C88-NF45
Format - Memory
RAM
Memory Type
NVSRAM (Non-Volatile SRAM)
Memory Size
256K (32K x 8)
Speed
45ns
Interface
Parallel
Voltage - Supply
4.5 V ~ 5.5 V
Operating Temperature
0°C ~ 70°C
Package / Case
32-SOIC (7.5mm Width)
Word Size
8b
Organization
32Kx8
Density
256Kb
Interface Type
Parallel
Access Time (max)
45ns
Operating Supply Voltage (typ)
5V
Package Type
SOIC
Operating Temperature Classification
Commercial
Operating Supply Voltage (max)
5.5V
Operating Supply Voltage (min)
4.5V
Operating Temp Range
0C to 70C
Pin Count
32
Mounting
Surface Mount
Supply Current
70mA
Lead Free Status / RoHS Status
Contains lead / RoHS non-compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
STK14C88-NF45
Manufacturer:
SIMTER
Quantity:
20 000
Company:
Part Number:
STK14C88-NF45I
Manufacturer:
SIMTEK
Quantity:
5 947
Part Number:
STK14C88-NF45I
Manufacturer:
SIMTEK
Quantity:
20 000
Company:
Part Number:
STK14C88-NF45ITR
Manufacturer:
SIMTEK
Quantity:
7 145
Hardware STORE (HSB) Operation
The STK14C88-3 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 STK14C88-3 conditionally initiates a STORE
operation after t
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. Pull up this
pin with an external 10K ohm resistor to V
a driver.
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,
the STK14C88-3 continues SRAM operations for t
t
is in progress when HSB is pulled LOW, it allows a time, t
to complete. However, any SRAM WRITE cycles requested after
HSB goes LOW are inhibited until HSB returns HIGH.
The HSB pin is used to synchronize multiple STK14C88-3 while
using a single larger capacitor. To operate in this mode, the HSB
pin is connected together to the HSB pins from the other
STK14C88-3. An external pull up resistor to V
since HSB acts as an open drain pull down. The V
the other STK14C88-3 parts are tied together and share a single
Document Number: 001-50592 Rev. *B
Figure 3. AutoStore Inhibit Mode
DELAY
, multiple SRAM READ operations take place. If a WRITE
DELAY
. An actual STORE cycle only begins if a
CAP
if HSB is used as
CAP
CAP
DELAY
is required,
pins from
. During
DELAY
capacitor. The capacitor size is scaled by the number of devices
connected to it. When any one of the STK14C88-3 detects a
power loss and asserts HSB, the common HSB pin causes all
parts to request a STORE cycle. (A STORE takes place in those
STK14C88-3 that are written since the last nonvolatile cycle.)
During any STORE operation, regardless of how it is initiated,
the STK14C88-3 continues to drive the HSB pin LOW, releasing
it only when the STORE is complete. After completing the
STORE operation, the STK14C88-3 remains disabled until the
HSB pin returns HIGH.
If HSB is not used, it is left unconnected.
Hardware RECALL (Power Up)
During power up or after any low power condition (V
V
once again exceeds the sense voltage of V
cycle is automatically initiated and takes t
If the STK14C88-3 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 V
Software STORE
Data is transferred from the SRAM to the nonvolatile memory by
a software address sequence. The STK14C88-3 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:
The software sequence is clocked with CE 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
t
READ and WRITE operation.
1. Read address 0x0E38, Valid READ
2. Read address 0x31C7, Valid READ
3. Read address 0x03E0, Valid READ
4. Read address 0x3C1F, Valid READ
5. Read address 0x303F, Valid READ
6. Read address 0x0FC0, Initiate STORE cycle
STORE
RESET
), an internal RECALL request is latched. When V
cycle time is fulfilled, the SRAM is again activated for
CC
or between CE and system V
HRECALL
STK14C88-3
SWITCH
CC
.
to complete.
Page 5 of 17
, a RECALL
CC
CC
<
[+] Feedback
[+] Feedback
[+] Feedback