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參數(shù)資料
| 型號： | DS1644-120 |
| 英文描述： | Nonvolatile Timekeeping RAM |
| 中文描述： | 非易失性內(nèi)存時鐘 |
| 文件頁數(shù)： | 5/11頁 |
| 文件大小： | 108K |
| 代理商： | DS1644-120 |
DS1644LPM
041697 5/11
DATA RETENTION MODE
When V
CC
is within nominal limits (V
CC
> 4.5 volts) the
DS1644L can be accessed as described above with
read or write cycles. However, when V
CC
is below the
power fail point V
PF
(point at which write protection oc-
curs) the internal clock registers and RAM are blocked
from access. This is accomplished internally by inhibit-
ing access via the CE signal. At this time the power–fail
output signal (PFO) will be driven active low and will
remain active until V
CC
returns to nominal levels. When
V
CC
falls below the level of the internal battery supply,
power input is switched from the V
CC
pin to the internal
battery and clock activity, RAM, and clock data are
maintained from the battery until V
CC
is returned to
nominal level.
INTERNAL BATTERY LONGEVITY
The DS1644L has a self contained lithium power source
that is designed to provide energy for clock activity, and
clock and RAM data retention when the V
CC
supply is
not present. The capability of this internal power supply
is sufficient to power the DS1644L continuously for the
life of the equipment in which it is installed. For specifi-
cation purposes, the life expectancy is 10 years at 25
°
C
with the internal clock oscillator running in the absence
of V
CC
power. The DS1644L is shipped from Dallas
Semiconductor with the clock oscillator turned off, so
the expected life should be considered to start from the
time the clock oscillator is first turned on. Actual life ex-
pectancy of the DS1644L will be much longer than 10
years since no internal lithium battery energy is con-
sumed when V
CC
is present. In fact, in most applica-
tions, the life expectancy of the DS1644L will be approx-
imately equal to the shelf life (expected useful life of the
lithium battery with no load attached) of the lithium bat-
tery which may prove to be as long as 20 years.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS1644L-120 | Nonvolatile Timekeeping RAM |
| DS1644L-150 | Nonvolatile Timekeeping RAM |
| DS1644LPM | Nonvolatile Timekeeping RAM |
| DS1644 | Nonvolatile Timekeeping RAM |
| DS1666-010 | Audio Digital Resistor |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1644-120+ | 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 |
| DS1644-15 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock |
| DS1644J | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Quad Clock Driver |
| DS1644L-12 | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Real-Time Clock |
| DS1644L-120 | 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 |
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