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參數(shù)資料
| 型號： | DS1742 |
| 廠商： | Maxim Integrated Products, Inc. |
| 英文描述： | Y2KC Nonvolatile Timekeeping RAM(Y2KC非易失性計(jì)時(shí)RAM) |
| 文件頁數(shù)： | 4/13頁 |
| 文件大?。?/td> | 95K |
| 代理商： | DS1742 |
DS1742
061998 4/13
t
DH
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 dis-
able the outputs t
WEZ
after WE goes active.
DATA RETENTION MODE
The 5 volt device is fully accessible and data can be writ-
ten 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 regis-
ters and SRAM are blocked from any access. 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.
If
V
PF
is less than V
BAT
, 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
BAT
,
the device power is switched from V
CC
to the backup
supply (V
BAT
) when V
CC
drops below V
BAT
.
RTC
operation and
SRAM
data are maintained from the
battery until
V
CC
is returned to nominal levels.
BATTERY LONGEVITY
The DS1742 has a lithium power source that is de-
signed 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 DS1742 continuously for the life of the
equipment in which it is installed. For specification pur-
poses, the life expectancy is 10 years at 25
°
C with the
internal clock oscillator running in the absence of V
CC
power. Each DS1742 is shipped from Dallas Semicon-
ductor 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 DS1742 will be much longer than
10 years since no lithium battery energy is consumed
when V
CC
is present.
BATTERY MONITOR
The DS1742 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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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1742-100 | 功能描述:實(shí)時(shí)時(shí)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(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1742-100+ | 功能描述:實(shí)時(shí)時(shí)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(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1742-100IND | 功能描述:實(shí)時(shí)時(shí)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(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1742-100IND+ | 功能描述:實(shí)時(shí)時(shí)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(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS1742-70 | 功能描述:實(shí)時(shí)時(shí)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(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
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