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参数资料
| 型号： | STK22C48-N35I |
| 英文描述： | DIODE TVS 11V 400W BIDIR 5% SMA |
| 中文描述： | NVRAM中（EEPROM的基础） |
| 文件页数： | 8/10页 |
| 文件大小： | 110K |
| 代理商： | STK22C48-N35I |
STK22C48
July 1999
3-28
In order to prevent unneeded
STORE
operations,
automatic
STORE
s as well as those initiated by
externally driving HSB low will be ignored unless at
least one
WRITE
operation has taken place since the
most recent
STORE
or
RECALL
cycle. An optional
pull-up resistor is shown connected to HSB. This
can be used to signal the system that the
AutoStore
cycle is in progress.
HSB OPERATION
The STK22C48 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 STK22C48 will
conditionally initiate a
STORE
operation after t
DELAY
;
an actual
STORE
cycle will only begin if a
WRITE
to
the
SRAM
took place since the last
STORE
or
RECALL
cycle. The HSB pin 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, the STK22C48 will
continue
SRAM
operations for t
DELAY
. During t
DELAY
,
multiple
SRAM
READ
operations may take place. If a
WRITE
is in progress when HSB is pulled low it will
be allowed a time, t
DELAY
, to complete. However, any
SRAM
WRITE
cycles requested after HSB goes low
will be inhibited until HSB returns high.
The HSB pin can be used to synchronize multiple
STK22C48s while using a single larger capacitor. To
operate in this mode the HSB pin should be con-
nected together to the HSB pins from the other
STK22C48s. An external pull-up resistor to + 5V is
required since HSB acts as an open drain pull down.
The V
CAP
pins from the other STK22C48 parts can
be tied together and share a single capacitor. The
capacitor size must be scaled by the number of
devices connected to it. When any one of the
STK22C48s detects a power loss and asserts HSB,
the common HSB pin will cause all parts to request
a
STORE
cycle (a
STORE
will take place in those
STK22C48s that have been written since the last
nonvolatile cycle).
During any
STORE
operation, regardless of how it
was initiated, the STK22C48 will continue to drive
the HSB pin low, releasing it only when the
STORE
is
complete. Upon completion of the
STORE
operation
the STK22C48 will remain disabled until the HSB
pin returns high.
If HSB is not used, it should be left unconnected.
PREVENTING STORES
The
STORE
function can be disabled on the fly by
holding HSB high with a driver capable of sourcing
30mA at a VOH of at least 2.2V, as it will have to
overpower the internal pull-down device that drives
HSB low for 20
μ
s at the onset of a
STORE
. When
the STK22C48 is connected for
AutoStore
opera-
tion (system V
CC
connected to V
CCX
and a 68
μ
F
capacitor on V
CAP
) and V
CC
crosses V
SWITCH
on the
way down, the STK22C48 will attempt to pull HSB
low; if HSB doesn
’
t actually get below V
IL
, the part
Figure 2:
AutoStore
Mode
6
6
μ
F
0
μ
F
B
1
+
1
1
14
28
27
26
15
Figure 3: System Power Mode
0
μ
F
B
1
1
1
14
28
27
26
15
Figure 4:
AutoStore
Inhibit Mode
0
μ
F
B
1
1
1
14
28
27
26
15
*If HSB is not used, it should be left unconnected.
相关PDF资料 |
PDF描述 |
|---|---|
| STK22C48-N45 | DIODE TVS 120V 400W BIDIR 5% SMA |
| STK22C48-N45I | DIODE TVS 130V 400W UNI 5% SMA |
| STK22C48-P20 | DIODE TVS 13V 400W UNI 5% SMA |
| STK22C48-P25 | DIODE TVS 14V 400W BIDIR 5% SMA |
| STK22C48-P25I | DIODE TVS 150V 400W BIDIR 5% SMA |
相关代理商/技术参数 |
参数描述 |
|---|---|
| STK22C48N45 | 制造商:未知厂家 制造商全称:未知厂家 功能描述:2K x 8 AutoStore⑩ nvSRAM QuantumTrap⑩ CMOS Nonvolatile Static RAM |
| STK22C48-N45 | 制造商:SIMTEK 制造商全称:Simtek Corporation 功能描述:2Kx8 AutoStore nvSRAM |
| STK22C48N45I | 制造商:未知厂家 制造商全称:未知厂家 功能描述:2K x 8 AutoStore⑩ nvSRAM QuantumTrap⑩ CMOS Nonvolatile Static RAM |
| STK22C48-N45I | 制造商:SIMTEK 制造商全称:Simtek Corporation 功能描述:2Kx8 AutoStore nvSRAM |
| STK22C48-N45ITR | 制造商:SIMTEK 制造商全称:Simtek Corporation 功能描述:2Kx8 AutoStore nvSRAM |
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