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参数资料
| 型号： | MAX6900EUT-T |
| 厂商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, PDSO6 |
| 封装： | SOT-23, 6 PIN |
| 文件页数： | 6/16页 |
| 文件大小： | 570K |
| 代理商： | MAX6900EUT-T |
MAX6900
I2C-Bus-Compatible Real-Time Clock
in a SOT23
14
______________________________________________________________________________________
f = f k (T0 - T )2
where:
f = change in frequency from +20°C.
f = nominal crystal frequency.
k = parabolic curvature constant (-0.035
±0.005ppm/°C2 for 32.768kHz watch crystals).
T0 = turnover temperature
(+25°C ±5°C for 32.768kHz watch crystals).
T = temperature of interest (°C).
For example: What is the worst-case change in oscilla-
tor frequency from +25°C to +45°C ambient?
f (worst case) = 32,768 (-0.04 / 1 10e6)
(20 -45)2 = -0.8192Hz
After 1 month, that translates to:
Assuming ±20ppm initial crystal tolerance (±53s initial
accuracy); total worst-case timekeeping error at the
end of 1 month = 66.96s - 53s = -119.96s or about 2
minutes (assumes negligible parasitic layout capaci-
tance).
Power-Supply Considerations
For most applications, a 0.1F capacitor from VCC to
GND provides adequate bypassing for the MAX6900.
Because the MAX6900’s supply current is well under
1A, a series resistor can be added to the supply to
reject extremely harsh noise.
PC Board Layout Considerations
When designing the PC board, keep the crystal as
close to the X1 and X2 pins of the MAX6900 as possi-
ble (Figure 11). Keep the trace lengths short and small
to avoid introducing excessive capacitive loading and
preventing unwanted noise pickup. Place a guard ring
around the crystal and tie the ring to ground to help iso-
late the crystal from unwanted noise pickup. Keep all
signals away from the crystal and the X1 and X2 pins to
prevent noise coupling. Finally, an additional local
ground plane on an adjacent PC board layer can be
added under the crystal to shield it from unwanted
pickup from traces on other layers of the board. This
plane should be isolated from the regular PC board
ground plane and tied to the GND pin of the MAX6900.
This plane needs to be no larger than the perimeter of
the guard ring. Ensure that this ground plane does not
contribute to significant capacitance between ground
and the traces that run from X1 and X2 to the crystal.
Chip Information
TRANSISTOR COUNT: 19,307
PROCESS: CMOS
t
31days
24
hr
day
60
min
hr
60
s
min
-0.8192Hz
32768Hz
66.96s
=
() ×
×
×
×
=
TYPICAL TEMPERATURE CHARACTERISITICS
(k = -0.035ppm/
°C2, TO = +25°C)
f(ppm)
TEMPERATURE (
°C)
-250
-200
-150
-100
-50
0
-50 -40 -30 -20 -10
0
10
20
25
30
40
50
60
70
80
90
Figure 10. Typical Temperature Curve for 32.768kHz Watch Crystal
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相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX6901EKA-W | 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MAX6901ETA | 制造商:Rochester Electronics LLC 功能描述: 制造商:Maxim Integrated Products 功能描述: |
| MAX6901ETA-T | 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| MAX6902ETA | 制造商:Rochester Electronics LLC 功能描述: |
| MAX6902ETA＋ | 制造商:Maxim Integrated Products 功能描述: |
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