參數(shù)資料
型號： LM2587SX-3.3/NOPB
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類： 穩(wěn)壓器
英文描述： 5 A SWITCHING REGULATOR, 100 kHz SWITCHING FREQ-MAX, PSSO5
封裝： TO-263, 5 PIN
文件頁數(shù)： 18/27頁
文件大?。?/td> 819K
代理商： LM2587SX-3.3/NOPB
Application Hints (Continued)
4) LM2587 package thermal resistances
θ
JA and
θ
JC (given
in the Electrical Characteristics).
Total power dissipated (P
D) by the LM2587 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 x
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 x(
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 compatable computers from a
National Semiconductor sales office in your area or the
National Semiconductor Customer Response Center (1-800-
272-9959).
European Magnetic Vendor
Contacts
Please contact the following addresses for details of local
distributors or representatives:
Coilcraft
21 Napier Place
Wardpark North Cumbernauld, Scotland G68 0LL Phone:
+44 1236 730 595 Fax: +44 1236 730 627
Pulse Engineering
Dunmore Road
Tuam Co. Galway, Ireland Phone: +353 93 24 107 Fax: +353
93 24 459
LM2587
www.national.com
25
相關PDF資料
PDF描述
LM2588-12MWC 9.5 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, UUC
LM2588-12MDC 9.5 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, UUC
LM2588-ADJMWC 9.5 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, UUC
LM2588T-12/NOPB 9.5 A SWITCHING REGULATOR, 200 kHz SWITCHING FREQ-MAX, PSFM7
LM2590HV3.3MDC 3 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC
相關代理商/技術參數(shù)
參數(shù)描述
LM2587SX-5.0 功能描述:直流/直流開關轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT
LM2587SX-5.0/NOPB 功能描述:直流/直流開關轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT
LM2587SXADJ 制造商:National Semiconductor 功能描述:Conv DC-DC Single Step Up 4V to 40V 6-Pin(5+Tab) TO-263 T/R
LM2587SX-ADJ 功能描述:直流/直流開關轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT
LM2587SX-ADJ/NOPB 功能描述:直流/直流開關轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開關頻率: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 安裝風格:SMD/SMT
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