參數(shù)資料
型號(hào): LM238
廠商: 意法半導(dǎo)體
元件分類: 基準(zhǔn)電壓源/電流源
英文描述: Very Low Drop Voltage Regulator with Inhabit(帶禁止的低壓差電壓穩(wěn)壓器)
中文描述: 非常低壓降穩(wěn)壓器與寓于(帶禁止的低壓差電壓穩(wěn)壓器)
文件頁數(shù): 7/12頁
文件大?。?/td> 185K
代理商: LM238
will be 0.05
(1 + R
2
/R
1
) or inthis case, 11.5 times
worse.
Figure 2shows the effectof resistancebetween the
regulator and 140
set resistor.
WiththeTO-3package,itiseasy tominimize there-
sistance from the case to the set resistor, by using
2 separate leads to the case. The ground of R2can
be returned near the ground of the load to provide
remote ground sensing and improve load regula-
tion.
PROTECTION DIODES
WhenexternalcapacitorsareusedwithanyICregu-
lator it is sometimes necessary to add protection
diodes to prevent the capacitors from discharging
through low current points into the regulator. Most
Figure 2 :
Regulator with Line Resistance inOut-
put Lead.
20
μ
F capacitors have low enoughinternal seriesre-
sistance to deliver 20A spikes when shorted. Al-
thoughthe surge is short, there is enough energy to
damage parts of the IC.
When anoutput capacitor is connected toa regula-
tor and the input isshorted, the output capacitor will
discharge into the output of the regulator. The dis-
chargecurrent depends on the value of thecapaci-
tor, the output voltage of the regulator, and therate
of decrease of V
I
. In the LM338 this discharge path
is through a large junction that isable tosustain 25A
surgewithno problem.Thisis nottrue ofother types
of positive regulators. For output capacitors of
100
μ
F or less at output of 15V or less, there is no
need to use diodes.
The bypass capacitor on the adjustment terminal
can discharge through a low current junction. Dis-
charge occurs when either the input or output is
shorted. Internal to the LM338 is a 50
resistor
which limits the peak discharge current. Noprotec-
tionis neededfor outputvoltages of25V or less and
10
μ
F capacitance. Figure 3 shows an LM338 with
protection diodes included for use with outputs
greaterthan 25V and high values of output capacit-
ance.
Figure 3 :
Regulator with Protection Diodes.
LM138-LM238-LM338
7/12
相關(guān)PDF資料
PDF描述
LM138 Very Low Drop Voltage Regulator with Inhabit(帶禁止的低壓差電壓穩(wěn)壓器)
LM338 Very Low Drop Voltage Regulator with Inhabit(帶禁止的低壓差電壓穩(wěn)壓器)
LM248 Quadruple Operational Amplifiers(四路運(yùn)放)
LM348 Quadruple Operational Amplifiers(四通用運(yùn)算放大器)
LM148 Quadruple Operational Amplifiers(四路通用運(yùn)放)
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