be kept valid throughout the write cycle. WE must return to the " />
參數(shù)資料
型號(hào)： DS1251WP-120
廠商： Maxim Integrated Products
文件頁(yè)數(shù)： 15/20頁(yè)
文件大?。?/td> 0K
描述： IC NVSRAM 4MBIT 120NS 34PCM
標(biāo)準(zhǔn)包裝： 40
類(lèi)型： Phantom 計(jì)時(shí)芯片
特點(diǎn)： 閏年，NVSRAM
存儲(chǔ)容量： 512KB
時(shí)間格式： HH:MM:SS:hh（12/24 小時(shí)）
數(shù)據(jù)格式： YY-MM-DD-dd
接口： 并聯(lián)
電源電壓： 2.97 V ~ 3.63 V
電壓 - 電源，電池： 3V
工作溫度： 0°C ~ 70°C
安裝類(lèi)型： 表面貼裝
封裝/外殼： 34-PowerCap? 模塊
供應(yīng)商設(shè)備封裝： 34-PowerCap 模塊
包裝： 管件
DS1251/DS1251P
4 of 20
be kept valid throughout the write cycle. WE must return to the high state for a minimum recovery time
(tWR ) before another cycle can be initiated. The OE control signal should be kept inactive (high) during
write cycles to avoid bus contention. However, if the output bus has been enabled ( CE and OE active)
then WE will disable the outputs in tODW from its falling edge.
DATA RETENTION MODE
The 5V device is fully accessible and data can be written or read only when VCC is greater than VPF.
However, when VCC is below the power-fail point, VPF (point at which write protection occurs), the
internal clock registers and SRAM are blocked from any access. When VCC falls below the battery switch
point, VSO (battery supply level), device power is switched from the VCC pin to the backup battery. RTC
operation and SRAM data are maintained from the battery until VCC is returned to nominal levels.
The 3.3V device is fully accessible and data can be written or read only when VCC is greater than VPF.
When VCC falls below the power-fail point, VPF , access to the device is inhibited. If VPF is less than VBAT,
the device power is switched from VCC to the backup supply (VBAT ) when VCC drops below VPF . If VPF is
greater than VBAT, the device power is switched from VCC to the backup supply (VBAT ) when VCC drops
below VBAT. RTC operation and SRAM data are maintained from the battery until VCC is returned to
nominal levels.
All control, data, and address signals must be powered down when VCC is powered down.
PHANTOM CLOCK OPERATION
Communication with the phantom clock is established by pattern recognition on a serial bit stream of
64 bits, which must be matched by executing 64 consecutive write cycles containing the proper data on
DQ0. All accesses that occur prior to recognition of the 64-bit pattern are directed to memory.
After recognition is established, the next 64 read or write cycles either extract or update data in the
phantom clock, and memory access is inhibited.
Data transfer to and from the timekeeping function is accomplished with a serial bit stream under control
of chip enable, output enable, and write enable. Initially, a read cycle to any memory location using the
CE
and OE control of the phantom clock starts the pattern recognition sequence by moving a pointer to
the first bit of the 64-bit comparison register. Next, 64 consecutive write cycles are executed using the
CE
and WE control of the SmartWatch. These 64 write cycles are used only to gain access to the
phantom clock. Therefore, any address to the memory in the socket is acceptable. However, the write
cycles generated to gain access to the phantom clock are also writing data to a location in the mated
RAM. The preferred way to manage this requirement is to set aside just one address location in RAM as a
phantom clock scratch pad. When the first write cycle is executed, it is compared to bit 0 of the 64-bit
comparison register. If a match is found, the pointer increments to the next location of the comparison
register and awaits the next write cycle. If a match is not found, the pointer does not advance and all
subsequent write cycles are ignored. If a read cycle occurs at any time during pattern recognition, the
present sequence is aborted and the comparison register pointer is reset. Pattern recognition continues for
a total of 64 write cycles as described above until all the bits in the comparison register have been
matched (Figure 1). With a correct match for 64 bits, the phantom clock is enabled and data transfer to or
相關(guān)PDF資料
PDF描述
M83723/73R2016N CONN RCPT 16POS JAM NUT W/SCKT
MCP4442T-502E/ST IC DGTL POT 129TAPS 5K 14TSSOP
DS1251YP-70 IC NVSRAM 4MBIT 70NS 34PCM
MCP4442T-103E/ST IC DGTL POT 129TAPS 10K 14TSSOP
MS3108E22-24P CONN PLUG 6POS RT ANG W/PINS
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS1251WP-120+ 功能描述:實(shí)時(shí)時(shí)鐘 4096K NV SRAM w/Phantom Clock RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS1251WP-120+C01 功能描述:實(shí)時(shí)時(shí)鐘 4096K NV SRAM w/Phantom Clock RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS1251WP-120+C02 功能描述:實(shí)時(shí)時(shí)鐘 4096K NV SRAM w/Phantom Clock RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS1251WP-120IND 功能描述:IC NVSRAM 4MBIT 120NS 34PCM RoHS:否 類(lèi)別:集成電路 (IC) >> 時(shí)鐘/計(jì)時(shí) - 實(shí)時(shí)時(shí)鐘 系列:- 產(chǎn)品培訓(xùn)模塊:Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:1 系列:- 類(lèi)型:時(shí)鐘/日歷 特點(diǎn):警報(bào)器，閏年，SRAM 存儲(chǔ)容量:- 時(shí)間格式:HH:MM:SS（12/24 小時(shí)） 數(shù)據(jù)格式:YY-MM-DD-dd 接口:SPI 電源電壓:2 V ~ 5.5 V 電壓 - 電源，電池:- 工作溫度:-40°C ~ 85°C 安裝類(lèi)型:表面貼裝 封裝/外殼:8-WDFN 裸露焊盤(pán) 供應(yīng)商設(shè)備封裝:8-TDFN EP 包裝:管件
DS1251WP-120IND+ 功能描述:實(shí)時(shí)時(shí)鐘 4096K NV SRAM w/Phantom Clock RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時(shí)間格式:HH:MM:SS RTC 存儲(chǔ)容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫(xiě)一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*