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參數(shù)資料
| 型號(hào)： | LM217M |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
| 中文描述： | 中型目前的1.2到37V可調(diào)電壓調(diào)節(jié)器 |
| 文件頁數(shù)： | 5/11頁 |
| 文件大?。?/td> | 115K |
| 代理商： | LM217M |
APPLICATIONINFORMATION
The LM317M provides an internal reference
voltage of
1.25V
between the
adjustments terminals. This is used to set a
constant current flow across an external resistor
divider (see fig.3), giving an output voltage V
O
of:
V
O
= V
REF
(
1
+
R
2
R
1
)
+ I
ADJ
R
2
The device was designed to minimize the term
I
ADJ
(100
μ
A max) and to maintain it very constant
with line and load changes. Usually, the error
term IADJ
R2 can be neglected. To obtain the
previous requirement, all the regulator quiescent
current is
returned to
imposing a minimumload current condition. If the
load is insufficient, the output voltagewill rise.
Since the LM317M is a floating regulator and
”sees” only the input-to-outputdifferential voltage,
supplies of very high voltage with respect to
ground can be regulatedas long as themaximum
input-to-output differential
Furthermore, programmable regulator are easily
obtainable and, by connecting a fixed resistor
between the adjustment and output, the device
can be usedas a precisioncurrent regulator.
In order to optimise the load regulation, the
current set resistor R1 (see fig. 3) should be tied
as close as possible to the regulator, while the
ground terminal of R2 should be near the ground
of the load to provideremote ground sensing.
output and
the output terminal,
is
not
exceeded.
EXTERNAL CAPACITORS (Fig.5)
Normally no capacitors are needed unless the
device is situated far from the input filter
capacitors; in which case an input bypass is
needed.
A 0.1
μ
F disc or 1
μ
F tantalium input bypass
capacitor (C
I
) is recommended to reduce the
sensitivity to input line impedance.
The adjustment terminal may be bypassed to
ground to improve ripple rejection. This capacitor
(C
adj
) prevents ripple from being amplified as the
output voltage is increased. A 10
μ
F capacitor
should improve ripple rejection about 80dB at
120Hz an a 10V application.
Although the LM317M is stable with no output
capacitance like any feedback circuit, certain
values
of
external
capacitance
excessive ringing. An output capacitance (C
O
) in
the form of a 1
μ
F tantalium or 25
μ
F aluminium
electrolytic capacitor on the output swamps this
effect and insures stability.
can
cause
PROTECTION DIODES (Fig.5)
When external capacitors are used with any IC
regulator it is sometimes necessary to add
protection diodes to prevent the capacitors from
discharging through low current points into the
regulator.
Figure
5
show
the
recommended
protection
voltages in excess of 25V or high capacitance
values (C
3
> 25
μ
F, C
2
> 10
μ
F). Diode D1
prevents C
3
from discharging through the IC
during an input short-circuit. The combination of
diodes D1 and D2 prevents C
2
from discarging
through the regulator during an input or output
short-circuit.
LM317M
diodes
with
for
the
output
START-UP BLOCK
It’s not guaranteed the Re-Boot of the device
when the junctiontemperatureis over 85
o
C.
LM217M/LM317M
5/11
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PDF描述 |
|---|---|
| LM217MDT | MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
| LM217MS | MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
| LM217MT | MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
| LM217MX | MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
| LM317M | Medium Current 1.2 TO 37V Adjustable Volatage Regulator(中等電流，1.2V至37V可調(diào)電壓穩(wěn)壓器) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM217M_08 | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Medium current 1.2 to 37 V adjustable voltage regulator |
| LM217MDT | 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 1.2-37V Adj Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L |
| LM217MDT-TR | 功能描述:線性穩(wěn)壓器 - 標(biāo)準(zhǔn) 1.2-37V Adj Positive RoHS:否 制造商:STMicroelectronics 輸出類型: 極性: 輸出電壓:1.8 V 輸出電流:150 mA 負(fù)載調(diào)節(jié): 最大輸入電壓:5.5 V 線路調(diào)整率: 最大工作溫度:+ 125 C 安裝風(fēng)格:SMD/SMT 封裝 / 箱體:SOT-323-5L |
| LM217MDT-TR-CUT TAPE | 制造商:ST 功能描述:LM217 Series 1.2 V 500 mA Adjustable Voltage Regulator - TO-252 |
| LM217MS | 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:MEDIUM CURRENT 1.2 TO 37V ADJUSTABLE VOLTAGE REGULATOR |
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