參數(shù)資料
型號(hào): LM2991T
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 基準(zhǔn)電壓源/電流源
英文描述: Negative Low Dropout Adjustable Regulator
中文描述: 3 V-24 V ADJUSTABLE NEGATIVE LDO REGULATOR, 1 V DROPOUT, PSFM5
封裝: STRAIGHT, TO-220, 5 PIN
文件頁(yè)數(shù): 5/11頁(yè)
文件大?。?/td> 338K
代理商: LM2991T
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
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2991T 制造商:Texas Instruments 功能描述:V REG ADJ -2/25V 2991 TO-220-5
LM2991T/LB01 制造商:Texas Instruments 功能描述:LDO Regulator Neg -3V to -24V 1A 5-Pin(5+Tab) TO-220 Rail
LM2991T/LB02 制造商:Texas Instruments 功能描述:LDO Regulator Neg -3V to -24V 1A 5-Pin(5+Tab) TO-220 Rail
LM2991T/LB03 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(dòng)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
LM2991T/LF03 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(dòng)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