数据搜索系统,热门电子元器件搜索 |
|
LM2576HVS-12 数据表(PDF) 11 Page - National Semiconductor (TI) |
|
|
LM2576HVS-12 数据表(HTML) 11 Page - National Semiconductor (TI) |
11 / 24 page LM2576 Series Buck Regulator Design Procedure PROCEDURE (Fixed Output Voltage Versions) EXAMPLE (Fixed Output Voltage Versions) Given: V OUT = Regulated Output Voltage (3.3V, 5V, 12V, or 15V) V IN(Max) = Maximum Input Voltage ILOAD(Max) = Maximum Load Current Given: V OUT =5VVIN(Max) = 15V ILOAD(Max) = 3A 1. Inductor Selection (L1) A. Select the correct Inductor value selection guide from Figures 3, 4, 5 or Figure 6. (Output voltages of 3.3V, 5V, 12V or 15V respectively). For other output voltages, see the design procedure for the adjustable version. B. From the inductor value selection guide, identify the inductance region intersected by V IN(Max) and ILOAD(Max), and note the inductor code for that region. C. Identify the inductor value from the inductor code, and select an appropriate inductor from the table shown in Figure 3. Part numbers are listed for three inductor manufacturers. The inductor chosen must be rated for operation at the LM2576 switching frequency (52 kHz) and for a current rating of 1.15 x I LOAD. For additional inductor information, see the inductor section in the Application Hints section of this data sheet. 1. Inductor Selection (L1) A. Use the selection guide shown in Figure 4. B. From the selection guide, the inductance area intersected by the 15V line and 3A line is L100. C. Inductor value required is 100 µH. From the table in Figure 3. Choose AIE 415-0930, Pulse Engineering PE92108, or Renco RL2444. 2. Output Capacitor Selection (C OUT)A. The value of the output capacitor together with the inductor defines the dominate pole-pair of the switching regulator loop. For stable operation and an acceptable output ripple voltage, (approximately 1% of the output voltage) a value between 100 µF and 470 µF is recommended. B. The capacitor’s voltage rating should be at least 1.5 times greater than the output voltage. For a 5V regulator, a rating of at least 8V is appropriate, and a 10V or 15V rating is recommended. Higher voltage electrolytic capacitors generally have lower ESR numbers, and for this reason it may be necessary to select a capacitor rated for a higher voltage than would normally be needed. 2. Output Capacitor Selection (C OUT)A. COUT = 680 µF to 2000 µF standard aluminum electrolytic. B.Capacitor voltage rating = 20V. 3. Catch Diode Selection (D1) A.The catch-diode current rating must be at least 1.2 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 LM2576. 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. 3. Catch Diode Selection (D1) A.For this example, a 3A current rating is adequate. B. Use a 20V 1N5823 or SR302 Schottky diode, or any of the suggested fast-recovery diodes shown in Figure 8. 4. Input Capacitor (C IN) An aluminum or tantalum electrolytic bypass capacitor located close to the regulator is needed for stable operation. 4. Input Capacitor (C IN) A 100 µF, 25V aluminum electrolytic capacitor located near the input and ground pins provides sufficient bypassing. www.national.com 11 |
类似零件编号 - LM2576HVS-12 |
|
类似说明 - LM2576HVS-12 |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |