SNVS106E – MAY 1999 – REVISED APRIL 2013
PROCEDURE (Adjustable Output Voltage Versions)
4. Catch Diode Selection (D1)
EXAMPLE (Adjustable Output Voltage Versions)
4. Catch Diode Selection (D1)
A.
The catch-diode current rating must be at least 1.2 times greater
A.
For this example, a 3A current rating is adequate.
than the maximum load current. Also, if the power supply design
B.
Use a 40V MBR340 or 31DQ04 Schottky diode, or any of the
must withstand a continuous output short, the diode should have a suggested fast-recovery diodes in
current rating equal to the maximum current limit of the LM2575. The
most stressful condition for this diode is an overload or shorted
output. See
B.
The reverse voltage rating of the diode should be at least 1.25
times the maximum input voltage.
5. Input Capacitor (C
IN
)
5. Input Capacitor (C
IN
)
An aluminum or tantalum electrolytic bypass capacitor located close A 100
μF
aluminum electrolytic capacitor located near the input and
to the regulator is needed for stable operation.
ground pins provides sufficient bypassing.
To further simplify the buck regulator design procedure, TI is making available computer design software to be
used with the Simple Switcher line of switching regulators.
Switchers Made Simple
(version 3.3) is available on
a (3½″) diskette for IBM compatible computers from a TI sales office in your area.
Table 1. Diode Selection Guide
V
R
20V
1N5817
MBR120P
SR102
1N5818
MBR130P
11DQ03
SR103
Schottky
1A
1N5820
MBR320
SR302
1N5821
MBR330
31DQ03
SR303
3A
1A
Fast Recovery
3A
The following
diodes are all
rated to 100V:
11DF1
MUR110
HER102
The following
diodes are all
rated to 100V:
31DF1
MURD310
HER302
30V
40V
1N5819
MBR140P
11DQ04
SR104
MBR150
11DQ05
SR105
MBR160
11DQ06
SR106
IN5822
MBR340
31DQ04
SR304
MBR350
31DQ05
SR305
MBR360
31DQ06
SR306
50V
60V
Table 2. Inductor Selection by Manufacturer's Part Number
Inductor Code
L100
L150
L220
L330
L470
L680
H150
H220
H330
H470
H680
H1000
(1)
(2)
(3)
16
Inductor Value
100
μH
150
μH
220
μH
330
μH
470
μH
680
μH
150
μH
220
μH
330
μH
470
μH
680
μH
1000
μH
Schott
(1)
Pulse Eng.
PE-92108
PE-53113
PE-52626
PE-52627
PE-53114
PE-52629
PE-53115
PE-53116
PE-53117
PE-53118
PE-53119
PE-53120
(2)
Renco
(3)
67127000
67127010
67127020
67127030
67127040
67127050
67127060
67127070
67127080
67127090
67127100
67127110
RL2444
RL1954
RL1953
RL1952
RL1951
RL1950
RL2445
RL2446
RL2447
RL1961
RL1960
RL1959
Schott Corp., (612) 475-1173, 1000 Parkers Lake Rd., Wayzata, MN 55391.
Pulse Engineering, (619) 674-8100, P.O. Box 12236, San Diego, CA 92112.
Renco Electronics Inc., (516) 586-5566, 60 Jeffryn Blvd. East, Deer Park, NY 11729.
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