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參數資料
| 型號： | LM9072T |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Dual Tracking Low-Dropout System Regulator |
| 中文描述： | DUAL OUTPUT, FIXED POSITIVE LDO REGULATOR, PZFM9 |
| 封裝： | POWER, TO-220, 9 PIN |
| 文件頁數： | 11/15頁 |
| 文件大小： | 477K |
| 代理商： | LM9072T |
Application Information
(Continued)
Input Stability
Low dropout voltage regulators which utilize a PNP power
transistor usually exhibit a large increase in current when in
dropout (V
<
5.5V). This increase is caused by the satura-
tion characteristics (
β
reduction) of the PNP transistor. To
significantly minimize this increase in current the LM9072
detects when the PNP enters saturation and reduces the op-
erating current.
This reduction in input current can create a stability problem
in applications with higher load current (
>
200 mA) where
the input voltage is applied through a long length of wire
which in effect add a significant amount of inductance in se-
ries with the input. The drop in input current may create a
positive input voltage transient which may take the PNP out
of saturation. If the input voltage is held constant at the
threshold where the PNP is going in and out of saturation, an
oscillation may be created.
This is only observed where a large series inductance is
present in the input supply line and when the rise and fall
time of the input supply is very slow. If the application and re-
moval of the input voltage changes at a rate greater than
500 mV/ms it will move through the dropout region of the
regulator (V
of 3V to 5.5V) too quickly for an oscillation to
be established.
In the event that an oscillation is present, input bypassing
can also help de-tune the resonance. Figure 7illustrates two
input bypassing approaches. The straightforward addition of
a larger valued electrolytic capacitor could suffice. in this
case however, if reverse battery connections are a possibility
it is necessary to add a series protection diode as shown to
prevent damaging the polarized input capacitor.
An alternative input bypassing scheme is also shown. This
eliminates the use of polarized input capacitors and a series
protection diode. The values shown were derived empirically
in a representative typical application. Appropriate values for
any given application require experimentation.
DS012906-22
FIGURE 6. Safety Latch-OFF
DS012906-23
FIGURE 7. Input Bypassing
L
www.national.com
11
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相關代理商/技術參數 |
參數描述 |
|---|---|
| LM9073 | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Dual High Current Low-Dropout System Regulator |
| LM9073S | 制造商:NSC 制造商全稱:National Semiconductor 功能描述:Dual High Current Low-Dropout System Regulator |
| LM9073SX | 功能描述:IC REG LDO 5V .7A/.1A TO-263-11 RoHS:否 類別:集成電路 (IC) >> PMIC - 穩壓器 - 線性 系列:- 標準包裝:1 系列:- 穩壓器拓撲結構:正，固定式 輸出電壓:4V 輸入電壓:最高 16V 電壓 - 壓降（標準）:0.28V @ 150mA 穩壓器數量:1 電流 - 輸出:150mA 電流 - 限制（最小）:- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:5-VFBGA 供應商設備封裝:5-uSMD 包裝:Digi-Reel® 其它名稱:LP2985AIBP-4.0DKR |
| LM9073T | 制造商:Rochester Electronics LLC 功能描述:5V DUAL OUTPUT TRACKING REGL - Bulk |
| LM9073T/NOPB | 功能描述:IC REG LDO 5V .7A/.1A TO-220-11 RoHS:是 類別:集成電路 (IC) >> PMIC - 穩壓器 - 線性 系列:- 標準包裝:1 系列:- 穩壓器拓撲結構:正，固定式 輸出電壓:4V 輸入電壓:最高 16V 電壓 - 壓降（標準）:0.28V @ 150mA 穩壓器數量:1 電流 - 輸出:150mA 電流 - 限制（最小）:- 工作溫度:-40°C ~ 125°C 安裝類型:表面貼裝 封裝/外殼:5-VFBGA 供應商設備封裝:5-uSMD 包裝:Digi-Reel® 其它名稱:LP2985AIBP-4.0DKR |
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