- 您现在的位置：买卖IC网 > PDF目录30746 > LM2597-ADJMDC (NATIONAL SEMICONDUCTOR CORP) 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC PDF资料下载
参数资料
| 型号： | LM2597-ADJMDC |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| 封装： | DIE |
| 文件页数： | 40/40页 |
| 文件大小： | 1019K |
| 代理商： | LM2597-ADJMDC |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页当前第40页
LM2597/LM2597HV 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) = 0.4A
1. Inductor Selection (L1)
A. Select the correct inductor value selection guide from
Figure 3, Figure 4,or Figure 5. (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 manufacturer’s
part numbers listed in
Figure 7.
1. Inductor Selection (L1)
A. Use the inductor selection guide for the 5V version shown
in
Figure 4.
B. From the inductor value selection guide shown in
Figure 4,
the inductance region intersected by the 12V horizontal line
and the 0.4A vertical line is 100 H, and the inductor code is
L20.
C. The inductance value required is 100 H. From the table in
Figure 7, go to the L20 line and choose an inductor part
number from any of the four manufacturers shown. (In most
instance, 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 82 F and 220 F
and low ESR solid tantalum capacitors between 15 F and
100 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 220 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 1.
This table contains different input voltages, output voltages,
and load currents, and lists various inductors and output
capacitors 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
Simpleversion 4.1 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 1, 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 0.5A 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.
120 F
25V
Panasonic HFQ Series
120 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, 120 F 10V aluminum electrolytic capacitor
would exhibit approximately 400 m
of ESR (see the curve in
Figure 17 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 capacitor with
a higher voltage rating (lower ESR) should be selected. A 16V
or 25V capacitor will reduce the ripple voltage by approxi-
mately half.
LM2597/LM2597HV
www.national.com
9
相关PDF资料 |
PDF描述 |
|---|---|
| LM2597HV-5MDC | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2597-3.3MWA | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2597HV-5MWC | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2597-5.0MDA | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2597-5.0MWA | 1.4 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2597HVM-12 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2597HVM-12/NOPB | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2597HVM-12/NOPB | 制造商:Texas Instruments 功能描述:DC/DC Converter IC |
| LM2597HVM-3.3 | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
| LM2597HVM-3.3/NOPB | 功能描述:直流/直流开关转换器 RoHS:否 制造商:STMicroelectronics 最大输入电压:4.5 V 开关频率:1.5 MHz 输出电压:4.6 V 输出电流:250 mA 输出端数量:2 最大工作温度:+ 85 C 安装风格:SMD/SMT |
发布紧急采购，3分钟左右您将得到回复。