參數(shù)資料
型號: DS17885N-3
廠商: MAXIM INTEGRATED PRODUCTS INC
元件分類: XO, clock
英文描述: 1 TIMER(S), REAL TIME CLOCK, PDIP24
封裝: DIP-24
文件頁數(shù): 35/38頁
文件大?。?/td> 410K
代理商: DS17885N-3
DS17885/DS17887
6 of 38
DS17885 ONLY
X1, X2 – Connections for a standard 32.768kHz quartz crystal. For greatest accuracy, the DS17885 must
be used with a crystal that has a specified load capacitance of either 6pF or 12.5pF. The crystal select
(CS) bit in extended-control register 4B is used to select operation with a 6pF or 12.5pF 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 about crystal selection and crystal layout considerations, refer to Application Note
58, “Crystal Considerations with Dallas Real-Time Clocks.” The DS17885 can also be driven by an
external 32.768kHz oscillator. In this configuration, the X1 pin is connected to the external oscillator
signal and the X2 pin is floated.
VBAT Battery input for any standard 3V lithium cell or other energy source. Battery voltage must be
held between 2.5V and 3.7V for proper operation. UL recognized to ensure against reverse charging
current when used in conjunction with a lithium battery. See “Conditions of Acceptability” at
POWER-DOWN/POWER-UP CONSIDERATIONS
The RTC function continues to operate and all of the RAM, time, calendar, and alarm memory locations
remain nonvolatile regardless of the level of the VCC input. When VCC is applied to the
DS17885/DS17887 and reaches a level of greater than VPF (power-fail trip point), the device becomes
accessible after tREC, provided that the oscillator is running and the oscillator countdown chain is not in
reset (Register A). This time period allows the system to stabilize after power is applied.
The DS17885/DS17887 is available in either a 3V or a 5V device.
The 5V device is fully accessible and data can be written and read only when VCC is greater than 4.5V.
When VCC is below 4.5V, read and writes are inhibited. However, the timekeeping function continues
unaffected by the lower input voltage. As VCC falls below the greater of VBAT and VBAUX, the RAM and
timekeeper are switched over to a lithium battery connected either to the VBAT pin or VBAUX pin.
The 3V device is fully accessible and data can be written or read only when VCC is greater than 2.7V.
When VCC falls below VPF, access to the device is inhibited. If VPF is less than VBAT and VBAUX, the
power supply is switched from VCC to the backup supply (the greater of VBAT and VBAUX) when VCC drops
below VPF. If VPF is greater than VBAT and VBAUX, the power supply is switched from VCC to the backup
supply when VCC drops below the larger of VBAT and VBAUX.
When VCC falls below VPF, 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(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
DS17885N-5 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:3V/5V Real-Time Clock
DS17885S-3 功能描述:實(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS17885S-3+ 功能描述:實(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS17885S-5 功能描述:實(shí)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(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube
DS17885S-5/T&R+ 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 8KBYTE 24SOIC - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC RTC 5V 8K NV RAM 24-SOIC