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參數(shù)資料
| 型號(hào)： | LM2698MM-ADJ |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | SIMPLE SWITCHER 1.35A Boost Regulator |
| 中文描述： | 2.4 A SWITCHING REGULATOR, 1500 kHz SWITCHING FREQ-MAX, PDSO8 |
| 封裝： | PLASTIC, MSOP-8 |
| 文件頁(yè)數(shù)： | 13/17頁(yè) |
| 文件大?。?/td> | 503K |
| 代理商： | LM2698MM-ADJ |
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Operation
(Continued)
Additional Comments on the Open Loop Frequency Re-
sponse
The procedure used here to pick the compensation network
will provide a good starting point. In most cases, these
values will be sufficient for a stable design. It is always
recommended to check the design in a real test setup. This
is easy to do with the aid of a dynamic load. Set the high and
low load values to your system requirements and switch
between the two at about 1kHz. View the output voltage with
an oscilloscope using AC coupling, and zoom in enough to
see the waveform react to the load change. Use the follow-
Application Information
ing table to determine if your design is stable. Remember to
use worst case conditions (V
IN(MIN)
, R
OUT(MIN)
, R
OUT(MAX)
).
Response
Conclusion
What to
Change
Make C
C1
larger
Nothing
Underdamped,
weak attenuation
Underdamped,
strong attenuation
Critically damped
Overdamped
Nearing instability
Stable
Stable
Stable
Nothing
Nothing
1.25MHz Boost Converter
Figure 6shows the LM2698 boosting 3.3V to 10V at 300mA.
As discussed in the COMPENSATION section, the R
of the internal FET in the LM2698 raises as the input voltage
drops below 5V (see Typical Performance Characteristics).
The minimum input voltage for this application is 2.5V, at
which point the R
DS(ON)
is approximately 200m
. Substitut-
ing these values in for Equation (1) it is found that either a
10 μH (1.25MHz operation) or a 22 μH (600kHz operation) is
necessary for a stable design. The circuit is operated at
1.25MHz to allow for a smaller inductance. From the Com-
pensator Design equations, R
C
is calculated to be 18.6k
,
and a 20k
resistor is used.
20012668
FIGURE 6. 3.3V to 10V Boost Converter
L
www.national.com
13
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2698MM-ADJ/NOPB | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 1.35A BOOST REG RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2698MM-ADJ/NOPB | 制造商:Texas Instruments 功能描述:DC/DC Converter (DC-DC) / Switching Regu |
| LM2698MMX-ADJ | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2698MMX-ADJ/NOPB | 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM26C1M5_-RPA | 制造商:National Semiconductor Corporation 功能描述: 制造商:Texas Instruments 功能描述: |
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