- 您现在的位置：买卖IC网 > PDF目录39246 > LM2596-12MWC (NATIONAL SEMICONDUCTOR CORP) 7.5 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC PDF资料下载
参数资料
| 型号： | LM2596-12MWC |
| 厂商： | NATIONAL SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 7.5 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| 封装： | WAFER |
| 文件页数： | 7/36页 |
| 文件大小： | 827K |
| 代理商： | LM2596-12MWC |
第1页第2页第3页第4页第5页第6页当前第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
LM2596 Series Buck Regulator Design Procedure (Adjustable Output)
(Continued)
PROCEDURE (Adjustable Output Voltage Version)
EXAMPLE (Adjustable Output Voltage Version)
5. Catch Diode Selection (D1)
A. The catch diode current rating must be at least 1.3 times
greater than the maximum load current. Also, if the power
supply design must withstand a continuous output short, the
diode should have a current rating equal to the maximum
current limit of the LM2596. The most stressful condition for
this diode is an overload or shorted output condition.
B. The reverse voltage rating of the diode should be at least
1.25 times the maximum input voltage.
C. This diode must be fast (short reverse recovery time) and
must be located close to the LM2596 using short leads and
short printed circuit traces. Because of their fast switching
speed and low forward voltage drop, Schottky diodes provide
the best performance and efficiency, and should be the first
choice, especially in low output voltage applications. Ultra-fast
recovery, or High-Efficiency rectifiers are also a good choice,
but some types with an abrupt turn-off characteristic may
cause instability or EMl problems. Ultra-fast recovery diodes
typically have reverse recovery times of 50 ns or less. Recti-
fiers such as the 1N4001 series are much too slow and should
not be used.
5. Catch Diode Selection (D1)
A. Refer to the table shown in
Figure 11. Schottky diodes
provide the best performance, and in this example a 5A, 40V,
1N5825 Schottky diode would be a good choice. The 5A diode
rating is more than adequate and will not be overstressed
even for a shorted output.
6. Input Capacitor (C
IN)
A low ESR aluminum or tantalum bypass capacitor is needed
between the input pin and ground to prevent large voltage
transients from appearing at the input. In addition, the RMS
current rating of the input capacitor should be selected to be at
least 12 the DC load current. The capacitor manufacturers
data sheet must be checked to assure that this current rating
is not exceeded. The curve shown in
Figure 13 shows typical
RMS current ratings for several different aluminum electrolytic
capacitor values.
This capacitor should be located close to the IC using short
leads and the voltage rating should be approximately 1.5
times the maximum input voltage.
If solid tantalum input capacitors are used, it is recomended
that they be surge current tested by the manufacturer.
Use caution when using a high dielectric constant ceramic
capacitor for input bypassing, because it may cause severe
ringing at the V
IN pin.
For additional information, see section on input capaci-
tors in application information section.
6. Input Capacitor (C
IN)
The important parameters for the Input capacitor are the input
voltage rating and the RMS current rating. With a nominal
input voltage of 28V, an aluminum electrolytic aluminum elec-
trolytic capacitor with a voltage rating greater than 42V (1.5 x
V
IN) would be needed. Since the the next higher capacitor
voltage rating is 50V, a 50V capacitor should be used. The
capacitor voltage rating of (1.5 x V
IN) is a conservative guide-
line, and can be modified somewhat if desired.
The RMS current rating requirement for the input capacitor of
a buck regulator is approximately 12 the DC load current. In
this example, with a 3A load, a capacitor with a RMS current
rating of at least 1.5A is needed.
The curves shown in
Figure 13 can be used to select an
appropriate input capacitor. From the curves, locate the 50V
line and note which capacitor values have RMS current ratings
greater than 1.5A. Either a 470 F or 680 F, 50V capacitor
could be used.
For a through hole design, a 680 F/50V electrolytic capacitor
(Panasonic HFQ series or Nichicon PL series or equivalent)
would be adequate. Other types or other manufacturers ca-
pacitors can be used provided the RMS ripple current ratings
are adequate.
For surface mount designs, solid tantalum capacitors can be
used, but caution must be exercised with regard to the capaci-
tor surge current rting (see Application Information or input
capacitors in this data sheet). The TPS series available from
AVX, and the 593D series from Sprague are both surge cur-
rent tested.
To further simplify the buck regulator design procedure, Na-
tional Semiconductor is making available computer design
software to be used with the Simple Switcher line ot switching
regulators. Switchers Made Simple (version 4.3 or later) is
available on a 312" diskette for IBM compatible computers.
LM2596
www.national.com
15
相关PDF资料 |
PDF描述 |
|---|---|
| LM2596-ADJMWC | 7.5 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2596-ADJMDC | 7.5 A SWITCHING REGULATOR, 173 kHz SWITCHING FREQ-MAX, UUC |
| LM2601MDC | 1-CHANNEL POWER SUPPLY SUPPORT CKT, UUC |
| LM2601MWC | 1-CHANNEL POWER SUPPLY SUPPORT CKT, UUC |
| LM2636MTC/NOPB | SWITCHING CONTROLLER, 2000 kHz SWITCHING FREQ-MAX, PDSO20 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LM2596ADPBCKGEVB | 功能描述:BOARD EVAL LM2596ADJ BUCK D2PAK RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| LM2596ATPBCKGEVB | 功能描述:BOARD EVAL LM2596ADJ BUCK TO-220 RoHS:是 类别:编程器，开发系统 >> 评估板 - DC/DC 与 AC/DC（离线）SMPS 系列:* 产品培训模块:Obsolescence Mitigation Program 标准包装:1 系列:True Shutdown™ 主要目的:DC/DC，步升 输出及类型:1，非隔离 功率 - 输出:- 输出电压:- 电流 - 输出:1A 输入电压:2.5 V ~ 5.5 V 稳压器拓扑结构:升压 频率 - 开关:3MHz 板类型:完全填充 已供物品:板 已用 IC / 零件:MAX8969 |
| LM2596DSADJG | 功能描述:直流/直流开关调节器 3A BUCK SWCH 150KHZ RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LM2596DSADJR4G | 功能描述:直流/直流开关调节器 3A BUCK SWCH 150KHZ RoHS:否 制造商:International Rectifier 最大输入电压:21 V 开关频率:1.5 MHz 输出电压:0.5 V to 0.86 V 输出电流:4 A 输出端数量: 最大工作温度: 安装风格:SMD/SMT 封装 / 箱体:PQFN 4 x 5 |
| LM2596S | 制造商:Texas Instruments 功能描述: |
发布紧急采购，3分钟左右您将得到回复。