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參數(shù)資料
| 型號： | DS1342U+ |
| 廠商： | Maxim Integrated Products |
| 文件頁數(shù)： | 14/16頁 |
| 文件大?。?/td> | 0K |
| 描述： | IC RTC I2C W/ALARM 8USOP |
| 產(chǎn)品培訓(xùn)模塊： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 標(biāo)準(zhǔn)包裝： | 50 |
| 類型： | 時鐘/日歷 |
| 特點： | 警報器，閏年，方波輸出 |
| 時間格式： | HH:MM:SS（12/24 小時） |
| 數(shù)據(jù)格式： | YY-MM-DD-dd |
| 接口： | I²C，2 線串口 |
| 電源電壓： | 1.8 V ~ 5.5 V |
| 電壓 - 電源，電池： | 1.3 V ~ 5.5 V |
| 工作溫度： | -40°C ~ 85°C |
| 安裝類型： | 表面貼裝 |
| 封裝/外殼： | 8-TSSOP，8-MSOP（0.118"，3.00mm 寬） |
| 供應(yīng)商設(shè)備封裝： | 8-uMAX |
| 包裝： | 管件 |
7
Maxim Integrated
Low-Current I2C RTCs for High-ESR Crystals
DS1341/DS1342
Detailed Description
The DS1341/DS1342 low-current RTCs are timekeeping
devices that consume an extremely low timekeeping cur-
rent, which permits longer life from a power supply. The
clock/calendar provides seconds, minutes, hours, day,
date, month, and year information. The date at the end of
the month is automatically adjusted for months with fewer
than 31 days, including corrections for leap year through
2099. The clock operates in either a 24hr or 12hr format
with an AM/PM indicator.
The DS1341/DS1342 use an external 32.768kHz crys-
tal. The oscillator circuit does not require any external
resistors or capacitors to operate. The devices support
a high-ESR crystal, which broadens the pool of usable
crystals for the device. The DS1342 uses a 12.5pF crys-
tal. The DS1341 uses a 6pF crystal, which decreases
oscillator current draw, but is less commonly available
than the 12.5pF crystals.
The DS1341/DS1342 also accept an external clock
reference for synchronization. The external clock can
be a 32.768kHz, 50Hz, 60Hz, or 1Hz source. When the
enable oscillator bit (EOSC) is a 0, the DS1341/DS1342
use the oscillator for timekeeping. If the enable external
clock input bit (ECLK) is set to 1, the time base derived
from the oscillator is compared to the 1Hz signal that is
derived from the CLKIN signal. The conditioned signal
drives the RTC time and date counters. If the oscillator
is disabled and the CLKIN signal is absent, the time and
date values remain static, provided that VCC remains at
a valid level.
When the external clock is lost or when the frequency
differs more than Q0.8% from the crystal frequency, the
signal derived from the crystal oscillator drives the RTC
counter.
When ECLK is set to 0, the RTC counter is always driven
with the signal derived from the crystal oscillator. When
the EOSC bit is a 1 and the external clock source is
selected, the RTC counter is always clocked by the sig-
nal from the CLKIN pin.
Address and data are transferred serially through an I2C
serial interface. Other features include two time-of-day
alarms, two interrupts, a programmable square-wave
output, and a bus timeout mechanism that resets the I2C
bus if it remains inactive for a minimum of tTIMEOUT.
Both devices are available in lead(Pb)-free/RoHS-
compliant, 8-pin FSOP or TDFN packages, and support
the -40NC to +85NC extended temperature range.
Oscillator Circuit
The DS1341/DS1342 use an external 32.768kHz crys-
tal. The oscillator circuit does not require any external
resistors or capacitors to operate. The DS1341 includes
integrated capacitive loading for a 6pF CL crystal, and
the DS1342 includes integrated capacitive loading for a
12.5pF CL crystal. See the Crystal Parameters table for
the external crystal parameters. The Functional Diagram
shows a simplified schematic of the oscillator circuit. The
startup time is usually less than 1 second when using a
crystal with the specified characteristics.
Clock Accuracy
When running from the internal oscillator, the accuracy of
the clock is dependent upon the accuracy of the crystal
and the accuracy of the match between the capacitive
load of the oscillator circuit and the capacitive load for
which the crystal was trimmed. Additional error is added
by crystal frequency drift caused by temperature shifts.
External circuit noise coupled into the oscillator circuit
can result in the clock running fast. Figure 2 shows a
typical PCB layout for isolation of the crystal and oscil-
lator from noise. Refer to Application Note 58: Crystal
Considerations with Dallas Real-Time Clocks for detailed
information.
Figure 2. Layout Example
CRYSTAL
X1
X2
GND
LOCAL GROUND PLANE (LAYER 2)
NOTE: AVOID ROUTING SIGNALS IN THE CROSSHATCHED AREA (UPPER LEFT-HAND
QUADRANT) OF THE PACKAGE UNLESS THERE IS A GROUND PLANE BETWEEN THE
SIGNAL LINE AND THE PACKAGE.
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1342U+ | 功能描述:實時時鐘 I2C RTC 12pF 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 |
| DS1342U+T&R | 制造商:Maxim Integrated Products 功能描述:I2C RTC 12.5PF UMAX PB FREE T&R - Tape and Reel 制造商:Maxim Integrated Products 功能描述:MXMDS1342U+T&R LOW-CURRENT IC RTCS FOR H 制造商:Maxim Integrated Products 功能描述:IC RTC I2C W/ALARM 8USOP 制造商:Maxim Integrated Products 功能描述:Real Time Clock I2C RTC 12pF |
| DS1342U+T&R | 功能描述:實時時鐘 I2C RTC 12pF 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 |
| DS1342U+TR | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Low-Current I2C RTCs for High-ESR Crystals |
| DS1343 | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Low-Current SPI/3-Wire RTCs |
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