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參數(shù)資料
| 型號： | DS1642-70 |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 9/13頁 |
| 文件大小： | 0K |
| 描述： | IC RAM TIMEKEEP NV 70NS 24-EDIP |
| 產(chǎn)品培訓模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標準包裝： | 14 |
| 類型： | 時鐘/日歷 |
| 特點： | 閏年，NVSRAM |
| 存儲容量： | 2KB |
| 時間格式： | HH:MM:SS（24 小時） |
| 數(shù)據(jù)格式： | YY-MM-DD-dd |
| 接口： | 并聯(lián) |
| 電源電壓： | 4.5 V ~ 5.5 V |
| 工作溫度： | 0°C ~ 70°C |
| 安裝類型： | 通孔 |
| 封裝/外殼： | 24-DIP 模塊（0.600"，15.24mm） |
| 供應商設備封裝： | 24-EDIP |
| 包裝： | 管件 |
DS1642
5 of 13
RETRIEVING DATA FROM RAM OR CLOCK
The DS1642 is in the read mode whenever WE (write enable) is high, and CE (chip enable) is low. The
device architecture allows ripple-through access to any of the address locations in the NV SRAM. Valid
data will be available at the DQ pins within tAA after the last address input is stable, providing that the CE
and OE access times and states are satisfied. If CE or OE access times are not met, valid data will be
available at the latter of chip enable access (tCEA) or at output enable access time (tOEA). The state of the
data input/output pins (DQ) is controlled by CE and OE . If the outputs are activated before tAA, the data
lines are driven to an intermediate state until tAA. If the address inputs are changed while CE and OE
remain valid, output data will remain valid for output data hold time (tOH) but will then go indeterminate
until the next address access.
WRITING DATA TO RAM OR CLOCK
The DS1642 is in the write mode whenever WE and CE are in their active state. The start of a write is
referenced to the latter occurring transition of WE or CE . The addresses must be held valid throughout
the cycle. CE or WE must return inactive for a minimum of tWR prior to the initiation of another read or
write cycle. Data in must be valid tDS prior to the end of write and remain valid for tDH afterward. In a
typical application, the OE signal will be high during a write cycle. However, OE can be active provided
that care is taken with the data bus to avoid bus contention. If OE is low prior to WE transitioning low
the data bus can become active with read data defined by the address inputs. A low transition on WE will
then disable the outputs tWEZ after WE goes active.
DATA RETENTION MODE
When VCC is within nominal limits (VCC > 4.5V) the DS1642 can be accessed as described above by read
or write cycles. However, when VCC is below the power-fail point VPF (point at which write protection
occurs) the internal clock registers and RAM is blocked from access. This is accomplished internally by
inhibiting access via the CE signal. When VCC falls below the level of the internal battery supply, power
input is switched from the VCC pin to the internal battery and clock activity, RAM, and clock data are
maintained from the battery until VCC is returned to nominal level.
BATTERY LONGEVITY
The DS1642 has a lithium power source that is designed to provide energy for clock activity, and clock
and RAM data retention when the VCC supply is not present. The capability of this internal power supply
is sufficient to power the DS1642 continuously for the life of the equipment in which it is installed. For
specification purposes, the life expectancy is 10 years at 25
C with the internal clock oscillator running in
the absence of VCC power. Each DS1642 is shipped from Dallas Semiconductor with its lithium energy
source disconnected, guaranteeing full energy capacity. When VCC is first applied at a level greater than
VPF, the lithium energy source is enabled for battery backup operation. Actual life expectancy of the
DS1642 will be much longer than 10 years since no lithium battery energy is consumed when VCC is
present.
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| DS1642-70+ | 功能描述:實時時鐘 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 時間格式:HH:MM:SS RTC 存儲容量: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: 安裝風格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1642-85 | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK PARALLEL 2KBYTE 24PIN EDIP - Bulk |
| DS1642-85+ | 功能描述:實時時鐘 NV Timekeeping RAM 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 時間格式:HH:MM:SS RTC 存儲容量: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: 安裝風格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS-1642ZJ | 制造商:Hikvision USA 功能描述:6" Outdoor Speed Dome Bracket, White, Ceiling Mount Bracket |
| DS1643 | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Nonvolatile Timekeeping RAMs |
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