- 您現(xiàn)在的位置：買(mǎi)賣(mài)IC網(wǎng) > PDF目錄379180 > DS1644L-120 Nonvolatile Timekeeping RAM PDF資料下載
參數(shù)資料
| 型號(hào)： | DS1644L-120 |
| 英文描述： | Nonvolatile Timekeeping RAM |
| 中文描述： | 非易失性?xún)?nèi)存時(shí)鐘 |
| 文件頁(yè)數(shù)： | 5/11頁(yè) |
| 文件大?。?/td> | 108K |
| 代理商： | DS1644L-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-150 | Nonvolatile Timekeeping RAM |
| DS1644LPM | Nonvolatile Timekeeping RAM |
| DS1644 | Nonvolatile Timekeeping RAM |
| DS1666-010 | Audio Digital Resistor |
| DS1666S-010 | Audio Digital Resistor |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1644L-15 | 制造商:未知廠(chǎng)家 制造商全稱(chēng):未知廠(chǎng)家 功能描述:Real-Time Clock |
| DS1644L-150 | 制造商:DALLAS 制造商全稱(chēng):Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644LPM | 制造商:DALLAS 制造商全稱(chēng):Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P | 制造商:MAXIM 制造商全稱(chēng):Maxim Integrated Products 功能描述:Nonvolatile Timekeeping RAM |
| DS1644P+120 | 制造商:DALLAS 制造商全稱(chēng):Dallas Semiconductor 功能描述:Nonvolatile Timekeeping RAM |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。