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參數(shù)資料
| 型號： | LM5008SDX |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 0.61 A SWITCHING REGULATOR, DSO8 |
| 封裝： | 4 X 4 MM, LLP-8 |
| 文件頁數(shù)： | 15/16頁 |
| 文件大小： | 378K |
| 代理商： | LM5008SDX |
20097905
FIGURE 9. Low Ripple Output Configuration
High Voltage Start-Up Regulator
The LM5008 contains an internal high voltage startup regu-
lator. The input pin (V
IN) can be connected directly to the line
voltages up to 95 Volts, with transient capability to 100 volts.
The regulator is internally current limited to 9.5mA at V
CC.
Upon power up, the regulator sources current into the external
capacitor at V
CC (C3). When the voltage on the VCC pin reach-
es the under-voltage lockout threshold of 6.3V, the buck
switch is enabled.
In applications involving a high value for V
IN, where power
dissipation in the V
CC regulator is a concern, an auxiliary volt-
age can be diode connected to the V
CC pin. Setting the
auxiliary voltage to 8.0 -14V will shut off the internal regulator,
reducing internal power dissipation. See Figure 10. The cur-
rent required into the V
CC pin is shown in Figure 2.
20097906
FIGURE 10. Self Biased Configuration
Regulation Comparator
The feedback voltage at FB is compared to an internal 2.5V
reference. In normal operation (the output voltage is regulat-
ed), an on-time period is initiated when the voltage at FB falls
below 2.5V. The buck switch will stay on for the on-time,
causing the FB voltage to rise above 2.5V. After the on-time
period, the buck switch will stay off until the FB voltage again
falls below 2.5V. During start-up, the FB voltage will be below
2.5V at the end of each on-time, resulting in the minimum off-
time of 300 ns. Bias current at the FB pin is nominally 100 nA.
Over-Voltage Comparator
The feedback voltage at FB is compared to an internal 2.875V
reference. If the voltage at FB rises above 2.875V the on-time
pulse is immediately terminated. This condition can occur if
the input voltage, or the output load, change suddenly. The
buck switch will not turn on again until the voltage at FB falls
below 2.5V.
www.national.com
8
LM5008
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM5008SDX/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(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 |
| LM5009 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:150 mA, 100V Step-Down Switching Regulator |
| LM5009_08 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:150 mA, 100V Step-Down Switching Regulator |
| LM5009A | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:100V, 150 mA Constant On-Time Buck Switching Regulator |
| LM5009AEVAL/NOPB | 功能描述:電源管理IC開發(fā)工具 LM5009A EVAL BOARD RoHS:否 制造商:Maxim Integrated 產(chǎn)品:Evaluation Kits 類型:Battery Management 工具用于評估:MAX17710GB 輸入電壓: 輸出電壓:1.8 V |
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