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參數(shù)資料
| 型號： | LM2991 |
| 廠商： | National Semiconductor Corporation |
| 英文描述： | Negative Low Dropout Adjustable Regulator |
| 中文描述： | 負(fù)低壓差可調(diào)穩(wěn)壓器 |
| 文件頁數(shù)： | 5/11頁 |
| 文件大?。?/td> | 338K |
| 代理商： | LM2991 |
Typical Performance Characteristics
(Continued)
Application Hints
EXTERNAL CAPACITORS
The LM2991 regulator requires an output capacitor to main-
tain stability. The capacitor must be at least 10 μF aluminum
electrolytic or 1 μF solid tantalum. The output capacitor’s
ESR must be less than 10
, or the zero added to the regu-
lator frequency response by the ESR could reduce the
phase margin, creating oscillations. The shaded area in the
Output Capacitor ESR graph indicates the recommended
ESR range.An input capacitor, of at least 1 μF solid tantalum
or 10 μF aluminum electrolytic, is also needed if the regulator
is situated more than 6 inches from the input power supply
filter.
MINIMUM LOAD
A minimum load current of 500 μA is required for proper op-
eration. The external resistor divider can provide the mini-
mum load, with the resistor from the adjust pin to ground set
to 2.4 k
.
SETTING THE OUTPUT VOLTAGE
The output voltage of the LM2991 is set externally by a resis-
tor divider using the following equation:
V
OUT
= V
REF
x (1 + R
2
/R
1
) (I
ADJ
x R
2
)
where V
= 1.21V. The output voltage can be pro-
grammed within the range of 3V to 24V, typically an even
Adjust Pin Current
DS011260-25
Low Voltage Behavior
DS011260-26
Maximum Power
Dissipation (TO-220)
DS011260-27
Maximum Power Dissipation
(TO-263) (See Note 3)
DS011260-28
Output Capacitor ESR Range
DS011260-5
www.national.com
5
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LM3-EWN1-01-N2 | SMD LED |
| LM3-PBG1-01-N1 | SMD LED |
| LM3-PBL1-01-N1 | SMD LED |
| LM3-PPG1-01-N1 | SMD LED |
| LM3046 | Transistor Array |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2991CS | 制造商:UNBRANDED 功能描述:LM2991CS *NIC* |
| LM2991GW-QML | 制造商:Texas Instruments 功能描述: |
| LM2991J-QML | 制造商:National Semiconductor Corporation 功能描述:LDO Regulator Neg -3V to -24V 1A 16-Pin CDIP Rail 制造商:National Semiconductor 功能描述:LDO Regulator Neg -3V to -24V 1A 16-Pin CDIP Rail |
| LM2991S | 功能描述:低壓差穩(wěn)壓器 - LDO RoHS:否 制造商:Texas Instruments 最大輸入電壓:36 V 輸出電壓:1.4 V to 20.5 V 回動電壓（最大值）:307 mV 輸出電流:1 A 負(fù)載調(diào)節(jié):0.3 % 輸出端數(shù)量: 輸出類型:Fixed 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:VQFN-20 |
| LM2991S | 制造商:Texas Instruments 功能描述:V REG ADJ -2/25V 2991 TO-263-5 |
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