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參數(shù)資料
| 型號： | DS17887-5 |
| 英文描述： | Real-Time Clock |
| 中文描述： | 實時時鐘 |
| 文件頁數(shù)： | 6/38頁 |
| 文件大?。?/td> | 515K |
| 代理商： | DS17887-5 |
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DS17885/DS17887
6 of 38
DS17885 ONLY
X1, X2 -
Connections for a standard 32.768 kHz quartz crystal. For greatest accuracy, the DS17885 must
be used with a crystal that has a specified load capacitance of either 6 pF or 12.5 pF. The Crystal Select
(CS) bit in Extended Control Register 4B is used to select operation with a 6 pF or 12.5 pF crystal. The
crystal is attached directly to the X1 and X2 pins. There is no need for external capacitors or resistors.
Note: X1 and X2 are very high impedance nodes. It is recommended that they and the crystal be guard-
ringed with ground and that high frequency signals be kept away from the crystal area.
For more information on crystal selection and crystal layout considerations, please consult Application
Note 58, “Crystal Considerations with Dallas Real Time Clocks.” The DS17885 can also be driven by an
external 32.768 kHz oscillator. In this configuration, the X1 pin is connected to the external oscillator
signal and the X2 pin is floated.
V
BAT
-
Battery input for any standard 3-volt lithium cell or other energy source. Battery voltage must be
held between 2.5 and 3.7 volts for proper operation.
POWER-DOWN/POWER-UP CONSIDERATIONS
The real time clock function will continue to operate and all of the RAM, time, calendar, and alarm
memory locations remain nonvolatile regardless of the level of the V
CC
input. When V
CC
is applied to the
DS17885/DS17887 and reaches a level of greater than V
PF
(power fail trip point), the device becomes
accessible after t
REC
, provided that the oscillator is running and the oscillator countdown chain is not in
reset (see Register A). This time period allows the system to stabilize after power is applied.
The DS17885/DS17887 is available in either a 3-volt or a 5-volt device.
The 5-volt device is fully accessible and data can be written and read only when V
CC
is greater than
4.5 volts. When V
CC
is below 4.5 volts, read and writes are inhibited. However, the timekeeping
function continues unaffected by the lower input voltage. As V
CC
falls below the greater of V
BAT
and
V
BAUX
, the RAM and timekeeper are switched over to a lithium battery connected either to the V
BAT
pin
or V
BAUX
pin.
The 3-volt device is fully accessible and data can be written or read only when V
CC
is greater than
2.7 volts. When V
CC
falls below V
PF
, access to the device is inhibited. If V
PF
is less than V
BAT
and
V
BAUX
, the power supply is switched from V
CC
to the backup supply (the greater of
VBAT
and V
BAUX
)
when VCC drops below V
PF
. If V
PF
is greater than V
BAT
and V
BAUX
, the power supply is switched from
V
CC
to the backup supply when V
CC
drops below the larger of V
BAT
and V
BAUX
.
When V
CC
falls below V
PF
, the chip is write-protected. With the possible exception of the
KS
,
PWR
,
RCLR
and SQW pins, all inputs are ignored and all outputs are in a high impedance state.
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相關PDF資料 |
PDF描述 |
|---|---|
| DS1801EN | Interface IC |
| DS1801N | Interface IC |
| DS1801SN | Interface IC |
| DS1802E | Digital Potentiometer |
| DS1802S | Digital Potentiometer |
相關代理商/技術參數(shù) |
參數(shù)描述 |
|---|---|
| DS17887-5 IND | 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 |
| DS17887-5+ | 功能描述:實時時鐘 3V/5V RTC 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 |
| DS17887-5IND | 功能描述:IC RTC 5V 8K NV RAM 24-EDIP RoHS:否 類別:集成電路 (IC) >> 時鐘/計時 - 實時時鐘 系列:- 產(chǎn)品培訓模塊:Obsolescence Mitigation Program 標準包裝:1 系列:- 類型:時鐘/日歷 特點:警報器，閏年，SRAM 存儲容量:- 時間格式:HH:MM:SS（12/24 小時） 數(shù)據(jù)格式:YY-MM-DD-dd 接口:SPI 電源電壓:2 V ~ 5.5 V 電壓 - 電源，電池:- 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:8-WDFN 裸露焊盤 供應商設備封裝:8-TDFN EP 包裝:管件 |
| DS17887-5IND+ | 功能描述:實時時鐘 3V/5V RTC 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 |
| DS17H531D | 制造商:SANYO 制造商全稱:Sanyo Semicon Device 功能描述:3-PHASE STEPPING SYSTEMS |
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