Electronic Components Datasheet Search
Selected language     English  ▼


LM2575T-5.0 Datasheet(PDF) 13 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor. Click here to check the latest version.
Part No. LM2575T-5.0
Description  SIMPLE SWITCHER 1A Step-Down Voltage Regulator
Download  27 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  NSC [National Semiconductor (TI)]
Homepage  http://www.national.com
Logo 

 13 page
background image
LM2575 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) = 20V ILOAD(Max) = 0.8A
1. Inductor Selection (L1) A. Select the correct Inductor
value selection guide from Figures 3, 4, 5, 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
I
LOAD(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 9. Part numbers are listed for three inductor
manufacturers. The inductor chosen must be rated for
operation at the LM2575 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 20V line and 0.8A line is
L330. C. Inductor value required is 330 µH. From the table
in Figure 9, choose AIE 415-0926, Pulse Engineering
PE-52627, or RL1952.
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 = 100 µF
to 470 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
LM2575. 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 1A
current rating is adequate. B. Use a 30V 1N5818 or SR103
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 47 µF, 25V aluminum electrolytic
capacitor located near the input and ground pins provides
sufficient bypassing.
www.national.com
13




Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27 


Datasheet Download



Related Electronics Part Number

Part NumberComponents DescriptionHtml ViewManufacturer
LM2599SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator with Features 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2677SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator with Sync 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2678SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2678S-12SIMPLE SWITCHER High Efficiency 5A Step-Down Voltage Regulator 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2576SIMPLE SWITCHER 3A Step-Down Voltage Regulator 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2679SIMPLE SWITCHER 5A Step-Down Voltage Regulator with Adjustable Current Limit 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2590HVSIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator with Features 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2591HVSIMPLE SWITCHER Power Converter 150 kHz 1A Step-Down Voltage Regulator 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2592HVSIMPLE SWITCHER Power Converter 150 kHz 2A Step-Down Voltage Regulator 1 2 3 4 5 MoreNational Semiconductor (TI)
LM2670SIMPLE SWITCHER High Efficiency 3A Step-Down Voltage Regulator with Sync 1 2 3 4 5 MoreNational Semiconductor (TI)

Link URL

Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Contact us   |   Privacy Policy   |   Bookmark   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com 2003 - 2017    


Mirror Sites
English : Alldatasheet.com  , Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp  |   Russian : Alldatasheetru.com
Korean : Alldatasheet.co.kr   |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com  |   Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl