參數(shù)資料
型號(hào)： LM2595J-5.0-QML
廠商： NATIONAL SEMICONDUCTOR CORP
元件分類： 穩(wěn)壓器
英文描述： 2.6 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, CDIP16
封裝： CERAMIC, DIP-16
文件頁(yè)數(shù)： 33/33頁(yè)
文件大?。?/td> 1016K
代理商： LM2595J-5.0-QML
LM2595 Series Buck Regulator Design Procedure (Fixed Output)
PROCEDURE (Fixed Output Voltage Version)
EXAMPLE (Fixed Output Voltage Version)
Given:
V
OUT = Regulated Output Voltage (3.3V, 5V or 12V)
V
IN(max) = Maximum DC Input Voltage
I
LOAD(max) = Maximum Load Current
Given:
V
OUT = 5V
V
IN(max) = 12V
I
LOAD(max) = 1A
1. Inductor Selection (L1)
A. Select the correct inductor value selection guide from
Fig-
ure 4 , Figure 5,or Figure 6. (Output voltages of 3.3V, 5V, or
12V respectively.) For all other voltages, see the design pro-
cedure for the adjustable version.
B. From the inductor value selection guide, identify the induc-
tance region intersected by the Maximum Input Voltage line
and the Maximum Load Current line. Each region is identified
by an inductance value and an inductor code (LXX).
C. Select an appropriate inductor from the four manufactur-
er’s part numbers listed in
Figure 8.
1. Inductor Selection (L1)
A. Use the inductor selection guide for the 5V version shown
in
Figure 5.
B. From the inductor value selection guide shown in
Figure 5,
the inductance region intersected by the 12V horizontal line
and the 1A vertical line is 68 H, and the inductor code is
L30.
C. The inductance value required is 68 H. From the table in
Figure 8, go to the L30 line and choose an inductor part num-
ber from any of the four manufacturers shown. (In most in-
stance, both through hole and surface mount inductors are
available.)
2. Output Capacitor Selection (C
OUT)
A. In the majority of applications, low ESR (Equivalent Series
Resistance) electrolytic capacitors between 47 F and 330
F and low ESR solid tantalum capacitors between 56 F
and 270 F provide the best results. This capacitor should be
located close to the IC using short capacitor leads and short
copper traces. Do not use capacitors larger than 330 F.
For additional information, see section on output capaci-
tors in application information section.
B. To simplify the capacitor selection procedure, refer to the
quick design component selection table shown in
Figure 2.
This table contains different input voltages, output voltages,
and load currents, and lists various inductors and output ca-
pacitors that will provide the best design solutions.
C. The capacitor voltage rating for electrolytic capacitors
should be at least 1.5 times greater than the output voltage,
and often much higher voltage ratings are needed to satisfy
the low ESR requirements for low output ripple voltage.
D. For computer aided design software, see
Switchers
Made Simple version 4.2 or later.
2. Output Capacitor Selection (C
OUT)
A. See section on output capacitors in application infor-
mation section.
B. From the quick design component selection table shown
in
Figure 2, locate the 5V output voltage section. In the load
current column, choose the load current line that is closest to
the current needed in your application, for this example, use
the 1A line. In the maximum input voltage column, select the
line that covers the input voltage needed in your application,
in this example, use the 15V line. Continuing on this line are
recommended inductors and capacitors that will provide the
best overall performance.
The capacitor list contains both through hole electrolytic and
surface mount tantalum capacitors from four different capaci-
tor manufacturers. It is recommended that both the manufac-
turers and the manufacturer’s series that are listed in the
table be used.
In this example aluminum electrolytic capacitors from several
different manufacturers are available with the range of ESR
numbers needed.
220 F
25V
Panasonic HFQ Series
220 F
25V
Nichicon PL Series
C. For a 5V output, a capacitor voltage rating at least 7.5V or
more is needed. But, in this example, even a low ESR,
switching grade, 220 F 10V aluminum electrolytic capacitor
would exhibit approximately 225 m
of ESR (see the curve
in
Figure 14 for the ESR vs voltage rating). This amount of
ESR would result in relatively high output ripple voltage. To
reduce the ripple to 1% of the output voltage, or less, a ca-
pacitor with a higher voltage rating (lower ESR) should be se-
lected. A 16V or 25V capacitor will reduce the ripple voltage
by approximately half.
Procedure continued on next page.
Example continued on next page.
www.national.com
9
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參數(shù)描述
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LM2595S-12 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)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
LM2595S12 制造商:Texas Instruments 功能描述:IC SWITCHING REG 1A 12V SMD 2595
LM2595S-12/NOPB 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)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
LM2595S-3.3 功能描述:直流/直流開(kāi)關(guān)轉(zhuǎn)換器 RoHS:否 制造商:STMicroelectronics 最大輸入電壓:4.5 V 開(kāi)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
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