欢迎访问ic37.com |
会员登录 免费注册
发布采购

STK22C48-SF45I 参数 Datasheet PDF下载

STK22C48-SF45I图片预览
型号: STK22C48-SF45I
PDF下载: 下载PDF文件 查看货源
内容描述: 2Kx8自动存储的nvSRAM [2Kx8 AutoStore nvSRAM]
分类和应用: 存储内存集成电路静态存储器光电二极管
文件页数/大小: 15 页 / 229 K
品牌: SIMTEK [ SIMTEK CORPORATION ]
 浏览型号STK22C48-SF45I的Datasheet PDF文件第5页浏览型号STK22C48-SF45I的Datasheet PDF文件第6页浏览型号STK22C48-SF45I的Datasheet PDF文件第7页浏览型号STK22C48-SF45I的Datasheet PDF文件第8页浏览型号STK22C48-SF45I的Datasheet PDF文件第10页浏览型号STK22C48-SF45I的Datasheet PDF文件第11页浏览型号STK22C48-SF45I的Datasheet PDF文件第12页浏览型号STK22C48-SF45I的Datasheet PDF文件第13页  
STK22C48  
least one WRITE operation has taken place since the  
most recent STORE or RECALL cycle.  
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 VCAP 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).  
If the power supply drops faster than 20 μs/volt  
before VCCX reaches VSWITCH, then a 2.2 ohm resistor  
should be inserted between VCCX and the system  
supply to avoid momentary excess of current  
between Vccx and Vcap.  
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  
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.  
conditionally initiate a STORE operation after tDELAY  
;
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. Pull up this pin with an external 10K  
If HSB is not used, it should be left unconnected.  
ohm resistor to V  
if HSB is used as a driver.  
CAP  
PREVENTING STORES  
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  
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 20μs at the onset of a STORE. When the  
STK22C48 is connected for AutoStore operation  
(system VCC connected to VCCX and a 68μF capacitor  
on VCAP) and VCC crosses VSWITCH on the way down,  
the STK22C48 will attempt to pull HSB low; if HSB  
doesn’t actually get below VIL, the part will stop try-  
ing to pull HSB low and abort the STORE attempt.  
continue SRAM operations for tDELAY. During tDELAY  
,
multiple SRAM READ operations may take place. If a  
WRITE is in progress when HSB is pulled low it will  
be allowed a time, tDELAY, 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  
10kΩ∗  
1
1
32  
31  
30  
32  
31  
30  
1
32  
31  
30  
+
16  
16  
17  
17  
16  
17  
Figure 2: AutoStore Mode  
Figure 3: System Power Mode  
Figure 4: AutoStore  
Inhibit Mode  
*If HSB is not used, it should be left unconnected.  
Rev 0.3  
Document Control #ML0004  
February 2007  
9