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参数资料
| 型号： | STK17T88-RF45TR |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | PROGRAMMABLE TIMER, PDSO48 |
| 封装： | 0.300 INCH, ROHS COMPLIANT, PLASTIC, SSOP-48 |
| 文件页数： | 4/29页 |
| 文件大小： | 535K |
| 代理商： | STK17T88-RF45TR |
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12
Jan, 2008
Document Control #ML0024 Rev 2.0
STK17T88
nvSRAM OPERATION
nvSRAM
The STK17T88 nvSRAM is made up of two func-
tional components paired in the same physical cell.
These are the SRAM memory cell and a nonvolatile
QuantumTrap cell. The SRAM memory cell operates
like a standard fast static RAM. Data in the SRAM
can be transferred to the nonvolatile cell (the
STORE operation), or from the nonvolatile cell to
SRAM (the RECALL operation). This unique archi-
tecture allows all cells to be stored and recalled in
parallel. During the STORE and RECALL operations
SRAM READ and WRITE operations are inhibited.
The STK17T88 supports unlimited read and writes
like a typical SRAM. In addition, it provides unlimited
RECALL operations from the nonvolatile cells and
up to 200K STORE operations.
SRAM READ
The STK17T88 performs a READ cycle whenever E
and G are low while W and HSB are high. The
address specified on pins A0-14 determine which of
the 32,768 data bytes will be accessed. When the
READ is initiated by an address transition, the out-
puts will be valid after a delay of tAVQV (READ cycle
#1). If the READ is initiated by E and G, the outputs
will be valid at tELQV or at tGLQV, whichever is later
(READ cycle #2). The data outputs will repeatedly
respond to address changes within the tAVQV access
time without the need for transitions on any control
input pins, and will remain valid until another
address change or until E or G is brought high, or W
and HSB is brought low.
SRAM WRITE
A WRITE cycle is performed whenever E and W are
low and HSB is high. The address inputs must be sta-
ble prior to entering the WRITE cycle and must
remain stable until either E or W goes high at the
end of the cycle. The data on the common I/O pins
DQ0-7 will be written into memory if it is valid tDVWH
before the end of a W controlled WRITE or tDVEH
before the end of an E controlled WRITE.
It is recommended that G be kept high during the
entire WRITE cycle to avoid data bus contention on
common I/O lines. If G is left low, internal circuitry
will turn off the output buffers tWLQZ after W goes
low.
AutoStore OPERATION
The STK17T88 stores data to nvSRAM using one of
three storage operations. These three operations
are Hardware Store (activated by HSB), Software
Store (activated by an address sequence), and
AutoStore (on power down).
AutoStore operation, a unique feature of Simtek
QuanumTrap technology that is a standard feature
on the STK17T88.
During normal operation, the device will draw cur-
rent from VCC to charge a capacitor connected to
the VCAP pin. This stored charge will be used by the
chip to perform a single STORE operation. If the
voltage on the VCC pin drops below VSWITCH, the
part will automatically disconnect the VCAP pin from
VCC. A STORE operation will be initiated with power
provided by the VCAP capacitor.
Figure 5 shows the proper connection of the storage
capacitor (VCAP) for automatic store operation.
Refer to the DC CHARACTERISTICS table for the
size of the capacitor. The voltage on the VCAP pin is
driven to 5V by a charge pump internal to the chip. A
pull up should be placed on W to hold it inactive dur-
ing power up.
To reduce unneeded nonvolatile stores, AutoStore
and Hardware Store operations will be ignored
unless at least one WRITE operation has taken
place since the most recent STORE or RECALL
cycle. Software initiated STORE cycles are per-
formed regardless of whether a WRITE operation
Figure 4: AutoStore Mode
VCC
V
CAP
10
k
O
h
m
0.1
F
VCC
VCAP
W
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|---|---|
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相关代理商/技术参数 |
参数描述 |
|---|---|
| STK17TA8-RF25 | 功能描述:NVRAM 128Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 数据总线宽度:8 bit 存储容量:1024 Kbit 组织:128 K x 8 接口类型:Parallel 访问时间:70 ns 电源电压-最大:5.5 V 电源电压-最小:4.5 V 工作电流:85 mA 最大工作温度:+ 70 C 最小工作温度:0 C 封装 / 箱体:EDIP 封装:Tube |
| STK17TA8-RF25I | 功能描述:NVRAM 128Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 数据总线宽度:8 bit 存储容量:1024 Kbit 组织:128 K x 8 接口类型:Parallel 访问时间:70 ns 电源电压-最大:5.5 V 电源电压-最小:4.5 V 工作电流:85 mA 最大工作温度:+ 70 C 最小工作温度:0 C 封装 / 箱体:EDIP 封装:Tube |
| STK17TA8-RF25IL | 制造商:Cypress Semiconductor 功能描述: |
| STK17TA8-RF25ITR | 功能描述:NVRAM 128Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 数据总线宽度:8 bit 存储容量:1024 Kbit 组织:128 K x 8 接口类型:Parallel 访问时间:70 ns 电源电压-最大:5.5 V 电源电压-最小:4.5 V 工作电流:85 mA 最大工作温度:+ 70 C 最小工作温度:0 C 封装 / 箱体:EDIP 封装:Tube |
| STK17TA8-RF25TR | 功能描述:NVRAM 128Kbx8+RTC 2.7-3.6V RoHS:否 制造商:Maxim Integrated 数据总线宽度:8 bit 存储容量:1024 Kbit 组织:128 K x 8 接口类型:Parallel 访问时间:70 ns 电源电压-最大:5.5 V 电源电压-最小:4.5 V 工作电流:85 mA 最大工作温度:+ 70 C 最小工作温度:0 C 封装 / 箱体:EDIP 封装:Tube |
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