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參數(shù)資料
| 型號(hào)： | LM2588T-12/NOPB |
| 廠商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分類： | 穩(wěn)壓器 |
| 英文描述： | 9.5 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PSFM7 |
| 封裝： | LEAD FREE, BENT STAGGERED, TO-220, 7 PIN |
| 文件頁數(shù)： | 21/30頁 |
| 文件大小： | 1280K |
| 代理商： | LM2588T-12/NOPB |
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Application Hints (Continued)
HEAT SINK/THERMAL CONSIDERATIONS
In many cases, a heat sink is not required to keep the
LM2588 junction temperature within the allowed operating
temperature range. For each application, to determine
whether or not a heat sink will be required, the following must
be identified:
1) Maximum ambient temperature (in the application).
2) Maximum regulator power dissipation (in the application).
3) Maximum allowed junction temperature (125C for the
LM2588). For a safe, conservative design, a temperature
approximately 15C cooler than the maximum junction tem-
perature should be selected (110C).
4) LM2588 package thermal resistances
θ
JA and
θ
JC (given
in the Electrical Characteristics).
Total power dissipated (P
D) by the LM2588 can be estimated
as follows:
Boost:
V
IN is the minimum input voltage, VOUT is the output voltage,
N is the transformer turns ratio, D is the duty cycle, and I
LOAD
is the maximum load current (and
∑I
LOAD is the sum of the
maximum load currents for multiple-output flyback regula-
tors). The duty cycle is given by:
Boost:
where V
F is the forward biased voltage of the diode and is
typically 0.5V for Schottky diodes and 0.8V for fast recovery
diodes. V
SAT is the switch saturation voltage and can be
found in the Characteristic Curves.
When no heat sink is used, the junction temperature rise is:
T
J =PD
θ
JA.
Adding the junction temperature rise to the maximum ambi-
ent temperature gives the actual operating junction tempera-
ture:
T
J =
T
J +TA.
If the operating junction temperature exceeds the maximum
junction temperatue in item 3 above, then a heat sink is
required. When using a heat sink, the junction temperature
rise can be determined by the following:
T
J =PD (
θ
JC +
θ
Interface +
θ
Heat Sink)
Again, the operating junction temperature will be:
T
J =
T
J +TA
As before, if the maximum junction temperature is exceeded,
a larger heat sink is required (one that has a lower thermal
resistance).
Included in the Switchers Made Simple design software is a
more precise (non-linear) thermal model that can be used to
determine junction temperature with different input-output
parameters or different component values. It can also calcu-
late the heat sink thermal resistance required to maintain the
regulator junction temperature below the maximum operat-
ing temperature.
To further simplify the flyback regulator design procedure,
National Semiconductor is making available computer de-
sign software Switchers Made Simple. Software is available
ona(312") diskette for IBM compatible computers from a
National Semiconductor sales office in your area or the
National
Semiconductor
Customer
Response
Center
(1-800-272-9959).
LM2588
www.national.com
28
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LM2588T-3.3 | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2588T-3.3/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2588T-5.0 | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2588T-5.0/NOPB | 功能描述:直流/直流開關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關(guān)頻率:1.5 MHz 輸出電壓:4.6 V 輸出電流:250 mA 輸出端數(shù)量:2 最大工作溫度:+ 85 C 安裝風(fēng)格:SMD/SMT |
| LM2588T50 | 制造商:Texas Instruments 功能描述:SWITCHING REG 5A 5.0V 2588 TO-220 |
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