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參數(shù)資料
| 型號： | DS1318 |
| 元件分類： | 通用總線功能 |
| 英文描述： | Parallel-Interface Elapsed Time Counter |
| 中文描述： | 并行接口歷時計數(shù)器 |
| 文件頁數(shù)： | 9/14頁 |
| 文件大小： | 158K |
| 代理商： | DS1318 |
D
Parallel-Interface Elapsed Time Counter
_____________________________________________________________________
9
input current is I
BAT
. The oscillator consumes most of
the current. If the oscillator is disabled, the data in the
registers remain static, and the battery input current is
I
BATDR
, which is primarily due to the leakage of the sta-
tic memory cells.
The DS1318 uses a standard parallel byte-wide interface
to access the register map. Table 1 summarizes the
modes of operation at various power-supply conditions.
Oscillator Circuit
The DS1318 uses an external 32.768kHz crystal. The
oscillator circuit does not require any external resistors
or capacitors to operate. Table 2 specifies several crys-
tal parameters for the external crystal, and Figure 1
shows a functional schematic of the oscillator circuit.
An enable bit in the control register controls the oscilla-
tor. Oscillator startup times are highly dependent upon
crystal characteristics, PC board leakage, and layout.
High ESR and excessive capacitive loads are the major
contributors to long startup times. A circuit using a
crystal with the recommended characteristics and
proper layout usually starts within one second.
An external 32.768kHz oscillator can also drive the
DS1318. In this configuration, the X1 pin is connected to
the external oscillator signal and the X2 pin is floated.
Clock Accuracy
The accuracy of the clock is dependent upon the accu-
racy 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 PC board layout
for isolation of the crystal and oscillator from noise. Refer
to
Application Note 58: Crystal Considerations with
Dallas Real-Time Clocks
for more detailed information.
PARAMETER
SYMBOL
f
O
ESR
C
L
MIN
TYP
32.768
MAX
UNITS
kHz
k
pF
Nominal Frequency
Series Resistance
Load Capacitance
50
12.5
Table 2. Crystal Specifications*
*
The crystal, traces, and crystal input pins should be isolated from RF generating signals. Refer to
Application Note 58: Crystal
Considerations for Dallas Real-Time Clocks
for additional specifications.
COUNTDOWN CHAIN
RTC
X1
X2
CRYSTAL
C
L
1
C
L
2
RTC REGISTERS
LOCAL GROUND PLANE (LAYER 2)
CRYSTAL
GND
X2
X1
NOTE:
AVOID ROUTING SIGNAL LINES
IN THE CROSSHATCHED AREA
(UPPER LEFT QUADRANT) OF
THE PACKAGE UNLESS THERE IS
A GROUND PLANE BETWEEN THE
SIGNAL LINE AND THE DEVICE PACKAGE.
Figure 1. Oscillator Circuit Showing Internal Bias Network
Figure 2. Layout Example
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS1318_10 | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Parallel-Interface Elapsed Time Counter |
| DS1318E | 制造商:MAXIM 制造商全稱:Maxim Integrated Products 功能描述:Parallel-Interface Elapsed Time Counter |
| DS1318E/GG8 | 制造商:Maxim Integrated Products 功能描述:44 BIT PARALLEL INTFACE ETC 24P TSS - Rail/Tube |
| DS1318E+ | 功能描述:實時時鐘 Parallel-Interface Elapsed Time Cntr 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 |
| DS1318E+T&R | 制造商:Maxim Integrated Products 功能描述:44 BIT PRLLEL INTFC ETC TRL LF - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC COUNTER ELAPSED TIME 24TSSOP |
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