參數(shù)資料
型號: LM2672N-12
廠商: NATIONAL SEMICONDUCTOR CORP
元件分類: 穩(wěn)壓器
英文描述: SIMPLE SWITCHER Power Converter High Efficiency 1A Step-Down Voltage Regulator with Features
中文描述: 2.2 A SWITCHING REGULATOR, 275 kHz SWITCHING FREQ-MAX, PDIP8
封裝: 0.300 INCH, PLASTIC, DIP-8
文件頁數(shù): 19/25頁
文件大?。?/td> 895K
代理商: LM2672N-12
LM2672 Series Buck Regulator Design Procedure (Adjustable Output)
(Continued)
PROCEDURE (Adjustable Output Voltage Version)
B.
Select an appropriate capacitor value and voltage rating,
using the capacitor code, from the output capacitor selection
table in
Figure 17
. There are two solid tantalum (surface mount)
capacitor manufacturers and four electrolytic (through hole)
capacitor manufacturers to choose from. It is recommended that
both the manufacturers and the manufacturer’s series that are
listed in the table be used. A table listing the manufacturers’
phone numbers is located in
Figure 11
.
EXAMPLE (Adjustable Output Voltage Version)
B.
From the output capacitor selection table in
Figure 17
,
choose a capacitor value (and voltage rating) that intersects the
capacitor code(s) selected in section A, C20.
The capacitance and voltage rating values corresponding to the
capacitor code C20 are the:
Surface Mount:
33 μF/25V
Sprague 594D Series.
33 μF/25V
AVX TPS Series.
Through Hole:
33 μF/25V
Sanyo OS-CON SC Series.
120 μF/35V
Sanyo MV-GX Series.
120 μF/35V
Nichicon PL Series.
120 μF/35V
Panasonic HFQ Series.
Other manufacturers or other types of capacitors may also be
used, provided the capacitor specifications (especially the 100
kHz ESR) closely match the characteristics of the capacitors
listed in the output capacitor table. Refer to the capacitor
manufacturers’ data sheet for this information.
4. Catch Diode Selection (D1)
A.
Refer to the table shown in
Figure 12
. Schottky diodes
provide the best performance, and in this example a 1A, 40V
Schottky diode would be a good choice. If the circuit must
withstand a continuous shorted output, a higher current (at least
2.2A) Schottky diode is recommended.
4. Catch Diode Selection (D1)
A.
In normal operation, the average current of the catch diode is
the load current times the catch diode duty cycle, 1-D (D is the
switch duty cycle, which is approximately V
OUT
/V
IN
). The largest
value of the catch diode average current occurs at the maximum
input voltage (minimum D). For normal operation, the catch
diode current rating must be at least 1.3 times greater than its
maximum average current. However, if the power supply design
must withstand a continuous output short, the diode should have
a current rating greater than the maximum current limit of the
LM2672. The most stressful condition for this diode is a shorted
output condition.
B.
The reverse voltage rating of the diode should be at least
1.25 times the maximum input voltage.
C.
Because of their fast switching speed and low forward
voltage drop, Schottky diodes provide the best performance and
efficiency. The Schottky diode must be located close to the
LM2672 using short leads and short printed circuit traces.
L
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相關(guān)PDF資料
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
LM2672N-12/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
LM2672N-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
LM2672N-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
LM2672N-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
LM2672N-5.0 制造商:Texas Instruments 功能描述:SWITCHING REG 1A 5.0V 2672 DIP8