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參數(shù)資料
| 型號： | DS1746P-70 |
| 英文描述： | Y2K-Compliant, Nonvolatile Timekeeping RAMs |
| 中文描述： | 千年蟲的，非易失時鐘存儲器 |
| 文件頁數(shù)： | 6/18頁 |
| 文件大小： | 224K |
| 代理商： | DS1746P-70 |
DS1746/DS1746P
6 of 18
DATA RETENTION MODE
The 5-volt device is fully accessible and data can be written or read only when V
CC
is greater than V
PF
.
However, when V
CC
is below the power fail point, V
PF
, (point at which write protection occurs) the
internal clock registers and SRAM are blocked from any access. At this time the power fail reset output
signal
)
RST
(
is driven active and will remain active until V
CC
returns to nominal levels. When V
CC
falls
below the battery switch point V
SO
(battery supply level), device power is switched from the V
CC
pin to
the backup battery. RTC operation and SRAM data are maintained from the battery until V
CC
is returned
to nominal levels. The 3.3 volt device is fully accessible and data can be written or read only when V
CC
is
greater than V
PF
. When V
CC
falls below the power fail point, V
PF
, access to the device is inhibited. At this
time the power fail reset output signal (RST) is driven active and will remain active until V
CC
returns to
nominal levels. If V
PF
is less than V
SO
, the device power is switched from V
CC
to the backup supply
(V
BAT
) when V
CC
drops below V
PF
.
If V
PF
is greater than V
SO
,
the device power is switched from V
CC
to
the backup supply (V
BAT
)
when V
CC
drops below V
SO
.
RTC operation and SRAM data are maintained
from the battery until V
CC
is returned to nominal levels. The RST signal is an open drain output and
requires a pull up. Except for the RST, all control, data, and address signals must be powered down
when V
CC
is powered down.
BATTERY LONGEVITY
The DS1746 has a 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 DS1746 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 V
CC
power. Each DS1746 is shipped from Dallas Semiconductor with its lithium energy
source disconnected, guaranteeing full energy capacity. When V
CC
is first applied at a level greater than
V
PF
, the lithium energy source is enabled for battery backup operation. Actual life expectancy of the
DS1746 will be much longer than 10 years since no lithium battery energy is consumed when V
CC
is
present.
BATTERY MONITOR
The DS1746 constantly monitors the battery voltage of the internal battery. The Battery Flag bit (bit 7) of
the day register is used to indicate the voltage level range of the battery. This bit is not writable and
should always be a one when read. If a zero is ever present, an exhausted lithium energy source is
indicated and both the contents of the RTC and RAM are questionable.
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PDF描述 |
|---|---|
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| DS17485E-3 | 3V/5V Real-Time Clock |
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1746P-70+ | 功能描述:實時時鐘 Timekeeping NV 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 |
| DS1746P-70IND | 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 |
| DS1746P-70IND+ | 功能描述:實時時鐘 Timekeeping NV 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 |
| DS1746W | 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Y2KC Nonvolatile Timekeeping RAM |
| DS1746W-120 | 功能描述:實時時鐘 Timekeeping NV 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 |
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